单选题The distance from which a certain light is visible is directly proportional to the wattage of the light bulb. If the light is visible from 16 meters when a 40 watt bulb is used, from what distance is the light visible when a 75 watt bulb is used?A 30 m

题目
单选题
The distance from which a certain light is visible is directly proportional to the wattage of the light bulb. If the light is visible from 16 meters when a 40 watt bulb is used, from what distance is the light visible when a 75 watt bulb is used?
A

30 meters

B

35 meters

C

51 meters

D

89 meters

E

91 meters

相似考题

1.Have you ever served the auxiliary engine to combustion heavy oil? What should be borne in mind when transferring oil; from heavy oil to light oil?

2.A head on situation shall be deemed to exist at night when a power-driven vessel sees another power-driven vessel ahead and ______.A.one sidelight and the masthead light are visibleB.the vessels will pass closer than half a mileC.both vessels sound one prolonged blastD.both sidelights and masthead light(s) are visible

3.The symbol which appears beside a light on a chart reads Gp Fl R (2) 10 sec 160 ft 19M. Which characteristic describes the light?A.It is visible 10 milesB.Its distinguishing number is 19MC.It has a radar reflectorD.None of the above

4.Edison invented the light bulb many years ago（改为被动语态）The light bulb__________ __________by Edison many years ago．

更多“单选题The distance from which a certain light is visible is directly proportional to the wattage of the light bulb. If the light is visible from 16 meters when a 40 watt bulb is used, from what distance is the light visible when a 75 watt bulb is used?A 30 m”相关问题

  • 第1题：

    When making landfall at night，the light from a powerful lighthouse may sometimes be seen before the lantern breaks the horizon．This light is called the ______．

    A.diffusion

    B.backscatter

    C.loom

    D.elevation


    正确答案：C

  • 第2题：

    共用题干
    Electromagnetic Energy

    1 White light seems to be a combination of all colors.The energy that comes from a source of light is
    not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy
    day it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce
    warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles away from the earth.Yet we can use energy from the sun because elec-
    tromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals
    travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an
    electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light
    have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro-
    magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating
    buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is
    useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right
    through solid objects.They can be used to detect and treat cancer. X-rays are used in industry to find hidden
    cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the
    sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is
    trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but
    the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If
    the.sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with
    electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the
    theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron
    （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi-
    cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that
    the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec-
    tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better
    methods of obtaining and using energy.

    When electron rearrangement takes place,_____________.
    A:electromagnetic energy
    B:electromagnetic energy travels through space
    C:came from the sun
    D:when a change in the nucleus of an atom takes place
    E:when the sunrays are fierce
    F:chemical energy is generated

    答案：F
    解析：
    第三段的第一句为主题句，意为：许多其他种类的能量也是不同类型的电磁能。该段列举了电磁能的具体例子，C项“Types of Electromagnetic Energy（电磁能的类型）”与主题句意思吻合，故选C。
    第四段的第二句为主题句，意为：我们的能量大多来自太阳。B项“The Most ImportantSource of Energy（最重要的能量来源）”与主题句意思吻合，故选B。
    第五段的最后一句为主题句，意为：我们现在相信太阳的能量来自核反应，在此过程 中，氢转变为氦。A项“Nuclear Reactions as the Lasting Source of the Sun ' s Energy（核反应是太阳能最持久的来源）”与主题句意思吻合，故选A。
    第六段的最后一句为主题句，意为：科学家仍在继续寻找获取和使用能量的新的、更好 的方法。E项“Seeking New Sources of Energy（寻找新的能源）”与主题句意思吻合，故选E。
    第一段的最后一句指出，“可见光和其他能产生热量和造成晒伤的能量都是电磁能的例子”。故选A。
    第二段的第二句指出，“我们能使用太阳能，因为电磁能可以在太空中穿梭”。故选B。
    第四段的最后一句指出，“其他的发电机靠煤炭驱动，但是，煤炭中储存的能量也来自 于太阳”。C项中的“came from the sun（来自太阳）”与原句意思相符，故选C。
    第五段的第五句指出，化学能来自于电子重组。故选F。第4部分：阅读理解第一篇 本文的主要内容是建筑工程师研究世贸大厦遗址及其周围幸存的建筑以设计出能够抵杭恐 怖袭击和爆炸的建筑。

  • 第3题：

    共用题干
    Electromagnetic Energy
    1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals travel from transmitters to receivers as low-energy electromagnetic waves.Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living.Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the theory was proposed , nuclear energy was harnessed（利用）by man.Chemical energy comes from electron （电子）rearrangement.Nuclear energy comes from a change in the nucleus of an atom.Compared with chemical reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of'power to generate electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.

    X-rays and gamma rays can be used to detect and treat cancer______.
    A:when it is absorbed by matter
    B:when it is cloudy
    C:because they can pass through solid objects
    D:when the sunrays are fierce.
    E:when a change in the nucleus of an atom takes place
    F:when electron rearrangement takes place

    答案：C
    解析：
    通读文章可知，第三段第一句是段落主题句，紧接着围绕第一句进行了具体阐述，根据第一句中出现的“types of electromagnetic energy”可知，第三段主要讲述几种不同种类的电磁能，应选择C项。
    根据第四段第一、二句可知，我们通常用电来生成电磁能，使用的很多能源都来自太阳。紧接着又表明，水能源于来自太阳的热能，煤储存的能量也是来自太阳。因此不难得出，第四段讲的是能量最重要的来源，即太阳。
    第五段开头提到太阳能的来源仍是个谜，随后对此进行了分析，最后得出太阳能来自核反应释放的能量。由此可知，第五段主要讲的是，氢原子转变为氦原子的核反应释放的能量是太阳能的来源。几个选项中只有A项提到核反应是太阳能的持久来源，因此选择A项。
    通读文章可知，第六段的最后一句是主题句。这句话的大意是：科学家正继续在寻找更好的新方法来获取并使用能源。几个选项中只有E项与之契合，因此选择E项。
    根据第一段第四句可知，你即便在感到凉爽的阴天，也有可能被阳光灼伤，因此选择B项。
    根据第三段第三、四句可知，红外线是电磁波，当它被物质吸收时，会产生能量。
    根据第三段倒数第二、三句可知，X射线和伽马射线之所以能用来探测和治疗癌症，是因为具有很多能量的x射线和伽马射线能穿透固体。
    根据第五段第五句可知，化学能是在电子重组时产生的。

  • 第4题：

    共用题干
    Electromagnetic Energy

    1 White light seems to be a combination of all colors.The energy that comes from a source of light is
    not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy
    day it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce
    warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles away from the earth.Yet we can use energy from the sun because elec-
    tromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals
    travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an
    electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light
    have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro-
    magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating
    buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is
    useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right
    through solid objects.They can be used to detect and treat cancer. X-rays are used in industry to find hidden
    cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the
    sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is
    trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but
    the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If
    the.sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with
    electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the
    theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron
    （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi-
    cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that
    the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec-
    tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better
    methods of obtaining and using energy.

    We can use energy from the sun because_____________.
    A:electromagnetic energy
    B:electromagnetic energy travels through space
    C:came from the sun
    D:when a change in the nucleus of an atom takes place
    E:when the sunrays are fierce
    F:chemical energy is generated

    答案：B
    解析：
    第三段的第一句为主题句，意为：许多其他种类的能量也是不同类型的电磁能。该段列举了电磁能的具体例子，C项“Types of Electromagnetic Energy（电磁能的类型）”与主题句意思吻合，故选C。
    第四段的第二句为主题句，意为：我们的能量大多来自太阳。B项“The Most ImportantSource of Energy（最重要的能量来源）”与主题句意思吻合，故选B。
    第五段的最后一句为主题句，意为：我们现在相信太阳的能量来自核反应，在此过程 中，氢转变为氦。A项“Nuclear Reactions as the Lasting Source of the Sun ' s Energy（核反应是太阳能最持久的来源）”与主题句意思吻合，故选A。
    第六段的最后一句为主题句，意为：科学家仍在继续寻找获取和使用能量的新的、更好 的方法。E项“Seeking New Sources of Energy（寻找新的能源）”与主题句意思吻合，故选E。
    第一段的最后一句指出，“可见光和其他能产生热量和造成晒伤的能量都是电磁能的例子”。故选A。
    第二段的第二句指出，“我们能使用太阳能，因为电磁能可以在太空中穿梭”。故选B。
    第四段的最后一句指出，“其他的发电机靠煤炭驱动，但是，煤炭中储存的能量也来自 于太阳”。C项中的“came from the sun（来自太阳）”与原句意思相符，故选C。
    第五段的第五句指出，化学能来自于电子重组。故选F。第4部分：阅读理解第一篇 本文的主要内容是建筑工程师研究世贸大厦遗址及其周围幸存的建筑以设计出能够抵杭恐 怖袭击和爆炸的建筑。

  • 第5题：

    共用题干
    Learn about Light
    1 .Ancient civilizations were amazed by the existence of light for thousands of years. The Greek philosophers believed that light was made up of countless,tiny particles that enter the human eye and create what we call vision. However,Empedocles and a Dutch scientist named Christian Huygens believed that light was like a wave. According to them,light spread out and travelled like a straight line. This theory was accepted during the 19th century.
    2 .In 1905,Albert Einstein published a research paper in which he explained what is re-ferred to as the photoelectric effect. This theory explains that particles make up light.The particles Einstein was referring to are weightless bundles（束）of electromagnetic（电磁）energy called photons（光子）.Today,scientists agree that light has a dual（二重）nature一it is part particle and part wave. It is a form of energy that allows us to see things around us.
    3 .Things that give off light are known as sources of light. During the day,the primary source of light is the sun. Other sources of light include stars,flames,flashlights,street lamps and glowing gases in glass tube.
    4 .When we draw the way light travels we always use straight lines. This is because nor-mally light rays travel in a straight line. However,there are some instances that can change the path and even the nature of light. They are reflection,absorption,interference（干扰）, etc.
    5 .Physicists have attempted to measure the speed of light since the early times. In 1849, Hippolyte Fizeau conducted an experiment by directing a beam of light to a mirror located kilometers away and placed a rotating cogwheel（旋转齿轮）between the beam and the mirror. From the rate of rotation of the wheel,number of wheel's teeth and distance of the mirror,he was able to calculate that the speed of light is 313 million meters per second. In a vacuum（真空）,however,the speed of light is 299,792,458 meters per second. This is about a million times faster than the speed of an airplane.

    Objects are visible to the human eye as light is______.
    A: sources of light
    B: the speed of light
    C: the path of light
    D: a straight line
    E: a beam of light
    F: a form of energy

    答案：F
    解析：
    该概括大意与完成句子所选的阅读材料为记述文，段落主题相对于论述文而言较松散，因此记述文中的段落大意往往需要考生根据自己的理解而归纳概括出来。解答概括大意题的技巧往往派不上用场。第二段主要讲述现代科学家认同了爱因斯坦的光电效应理论。因此可以判断A选项“当今人们如何解释光的性质”正确。
    第三段第一句“Things that give off light are known as sources of light.”就点明主旨，发光的物体是光源。所以B选项“什么是光源？”正确。
    第四段主要讲述光传播的问题，所以D选项“光是如何传播的”正确。
    第五段的关键字是speed of light，光速。所以C选项“物理学家如何测量光的速度”正确。
    题干意为“人们可以看见物体是因为光……。“从第二段最后一句可知，人们看见物体是因为光是一种能量。所以F项a form of energy正确的。
    题干意为“星星、火焰、手电筒都是……的例子。”第三段“Other sources of light include stars , flames , flashlights...”说明，这些都是光源的例子。所以A选项sourcesof light是正确的。
    题干意为“某些情况下，如反射和吸收可以改变……。”第四段中“there are some instances that can change the path and even the nature of light.They are reflection,ab-sorption , interference , etc.”这说明有一些情况可以改变光的路径。所以C选项the path of light是正确的。
    题干意为“Hippolyte Fizeau做了一个刚试……的实验。”文中最后一段 “Hippolyte Fizeau conducted an experiment by directing a beam of light to a mirror...he was able to calculate that the speed of light...”可知Hippolyte Fizeau通过实验计算出了光速。所以B选项是正确的。

  • 第6题：

    共用题干
    Electromagnetic Energy

    1 White light seems to be a combination of all colors.The energy that comes from a source of light is
    not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy
    day it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce
    warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles away from the earth.Yct we can use energy from die sun because elec-
    tromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signais
    travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an
    electromagnetic wave.When it is absorbed by matter,heat is produced.Wayes of infrared and visible light
    have more energy than waves of radio,television,or radar. Ultraviolet rays（紫外线）and X-rays are eleetro-
    magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating
    buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is
    useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right
    through solid objects.They can be used to detect and treat cancer。 X-rays are used in industry to find hidden
    cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the
    sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is
    trapped behind dams and then used to operate electric generators,Other generators are powered by coal,but
    the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If
    the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with
    electromagnetic radiation led to the theory that mass can be converted into energy．入bout forty years after the
    theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron
    （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi-
    cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that
    the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec-
    tricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better
    methods of obtaining and using energy.

    When electron rearrangement takes place_______________.
    A:electromagnetic energy
    B:electromagnetic energy travels through space
    C:came from the sun
    D:when a change in the nucleus of an atom takes place
    E:whlen the sunrays are fierce
    F:chemical energy is generated

    答案：F
    解析：
    第三段的第一句为主题句，意为：许多其他种类的能量也是不同类型的电磁能。该段 列举了电磁能的具体例子，C项“Types of Electromagnetic Energy（电磁能的类型）”与主题句意 思吻合，故选C。
    第四段的第二句为主题句，意为：我们的能量大多来白太阳。B项“The Most Important Source of Energy（最重要的能量来源）”与主题句意思吻合，故选B。
    第五段的最后一句为主题句，意为；我们现在相信太阳的能量来自核反应，在此过程 中，氢转变为氦。A项“Nuclear Reactions as the Lasting Source of the Sun' s Energy（核反应是太 阳能最持久的来源）”与主题句意思吻合，故选A。
    第六段的最后一句为主题句，意为：科学家仍在继续寻找获取和使用能量的新的、更好 的方法。E项“Seeking New Sources of Energy（寻找新的能源）”与主题句意思吻合，故选E。
    第一段的最后一句指出，“可见光和其他能产生热量和造成晒伤的能量都是电磁能的 例子”。故选A。
    第二段的第二句指出，“我们能使用太阳能，因为电磁能可以在太空中穿梭”。故选B。
    第四段的最后一句指出，“其他的发电机靠煤炭驱动，但是，煤炭中储存的能量也来自 于太阳”。C项中的“came from the sun (来自太阳）”与原句意思相符，故选C。
    第五段的第五句指出，化学能来自于电子重组。故选F。第4部分：阅读理解第一篇 本文介绍了引起食物中毒的原因及食物中毒的预防和治疗处理措施。

  • 第7题：

    共用题干
    Learn About Light

    1 Ancient civilizations were amazed by the existence of light for thousands of years?The Greek philoso-
    phrrs believed that light was made up of countless,tiny particles that enter the human eye and create what
    we call vision.However,Empedocles and a Dutch scientist named Christian Huygens believed that light wag
    like a wave.According to them,light spread out and travelled like a straight line.This theory was accepted
    during the 19th century.
    2 In 1905,Albert Einstein published a research paper in which he explained what is referred to as the
    photoelectric effect.This theory explains that particles make up light.The particles Einstein was referring to
    are weightless bundles（束）of electromagnetic（电磁）energy called photons（光子）.Today,scientists agree
    that light has a dual（二重）nature一it is part particle and part wave. It is a form of energy that allows us to
    see things around us.
    3 Things that give off light are known as sources of light.During the day,the primary source of light is
    the sun.Other sources of light include stars,flames,flashllights,street lamps and glowing gases in glass
    tube.
    4 When we draw the way light travels we always use straight lines.This is because normally light rays
    travel in a straight line.However,there are some instances that can change the path and even the nature of
    light. They are reflection,absorption,interference（干扰）,etc.
    5 Physicists have attempted to measure the speed of light since the early times.In 1849,Hippolyte
    Fizeau conducted an experiment by directing a beam of light to a mirror located kilometers away and placed
    a rotating cogwheel（旋转齿轮）between the beam and the mirror. From the rate of rotation of the wheel,
    number of wheel'S teeth and distance of the mirror,he was able to calculate that the speed of light is 313
    million meters per second.In a vacuum（真空）,however,the speed of light is 299,792,458 meters per
    second.This is about a million times faster than the speed of an airplane.

    Objects are visible to the human eye as light is_______.
    A:sources of light
    B:the speed of light
    C:the path of light
    D:a straight line
    E:a beam of light
    F:a form of energy

    答案：F
    解析：
    第二段前半部分介绍了爱因斯坦的光电效应理论，后半部分则介绍了现代科学家对于 光的看法：他们认为光具有二重性。
    第三段主要讲述了光源的定义和常见的光源，故选B。
    第四段主要讲述了光的传播方式以及影响光的传播方式和性质的因素，故选D。
    第五段以Flippolvte Fizeau为例，介绍了物理学家是如何测定光速的，故选C。
    文章第一段中只提到光像一条直线一样传播，而并非说光是一条直线。另外，由第二段 最后一句话“it is a form of energy that allows us to see things around us.”可知，光是一种能让我 们看到周围事物的能量，故选F。
    山第三段的最后一句话“Other sources of light include stars, flames, flashlights, street lamps and glowing gases in glass tube.”可知，应选A。
    由第四段最后两句话可知，一些因素会影响光的传播路径，这些因素包括光的反射、光 的吸收和光的干扰，故选C。
    由第五段的实例可知,Hippolyte Fizcau是用一束光测出了光的速度，故选B。第4部分；阅读理解第一篇 本篇文章主要讲述了石墨烯对于将未电子学发展的重要性以及人们可用一种简单的方式发 现石、墨烯。

  • 第8题：

    单选题
    Some lights used as aids to marine navigation have a red sector to indicate a danger area. The limits of a colored sector of a light are listed in the Light List in which of the following manners?（）
    A

    Geographical positions outlining the area of the sector

    B

    True bearings as observed from the ship toward the light

    C

    An outline of the area of the sector

    D

    True bearings as observed from the light toward the ship


    正确答案： C
    解析： 暂无解析

  • 第9题：

    单选题
    The color of the exhaust from a diesel engine should be （）
    A

    clear

    B

    hazy light brown

    C

    hazy light blue

    D

    hazy light grey


    正确答案： D
    解析： 暂无解析

  • 第10题：

    单选题
    The minimum length of a boat painter for a lifeboat in ocean service is（）.
    A

    60 fathoms

    B

    the distance from the main deck to the light waterline

    C

    twice the distance from the main deck to the light waterline or 50 feet whichever is greater

    D

    two times the distance from the boat deck to the light waterline or 50 feet whichever is greater


    正确答案： B
    解析： 暂无解析

  • 第11题：

    单选题
    When making landfall at night，you can determine if a light is a major light or an offshore buoy by（）.
    A

    the intensity of the light

    B

    checking the period and characteristics against the Light List

    C

    the color，because the buoy will have only a red or a green light

    D

    Any of the above can be used to identify the light


    正确答案： A
    解析： 暂无解析

  • 第12题：

    单选题
    A flashing light is a light that（）.
    A

    flashes at regular intervals at a frequency of 120 flashes or more per minute

    B

    is yellow in color

    C

    is visible over an arc of the horizon of not less than 180°nor more than 225°

    D

    All of the above


    正确答案： B
    解析： 暂无解析

  • 第13题：

    共用题干
    Electromagnetic Energy
    1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals travel from transmitters to receivers as low-energy electromagnetic waves.Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living.Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the theory was proposed , nuclear energy was harnessed（利用）by man.Chemical energy comes from electron （电子）rearrangement.Nuclear energy comes from a change in the nucleus of an atom.Compared with chemical reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of'power to generate electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.

    Infrared radiation can produce heat______.
    A:when it is absorbed by matter
    B:when it is cloudy
    C:because they can pass through solid objects
    D:when the sunrays are fierce.
    E:when a change in the nucleus of an atom takes place
    F:when electron rearrangement takes place

    答案：A
    解析：
    通读文章可知，第三段第一句是段落主题句，紧接着围绕第一句进行了具体阐述，根据第一句中出现的“types of electromagnetic energy”可知，第三段主要讲述几种不同种类的电磁能，应选择C项。
    根据第四段第一、二句可知，我们通常用电来生成电磁能，使用的很多能源都来自太阳。紧接着又表明，水能源于来自太阳的热能，煤储存的能量也是来自太阳。因此不难得出，第四段讲的是能量最重要的来源，即太阳。
    第五段开头提到太阳能的来源仍是个谜，随后对此进行了分析，最后得出太阳能来自核反应释放的能量。由此可知，第五段主要讲的是，氢原子转变为氦原子的核反应释放的能量是太阳能的来源。几个选项中只有A项提到核反应是太阳能的持久来源，因此选择A项。
    通读文章可知，第六段的最后一句是主题句。这句话的大意是：科学家正继续在寻找更好的新方法来获取并使用能源。几个选项中只有E项与之契合，因此选择E项。
    根据第一段第四句可知，你即便在感到凉爽的阴天，也有可能被阳光灼伤，因此选择B项。
    根据第三段第三、四句可知，红外线是电磁波，当它被物质吸收时，会产生能量。
    根据第三段倒数第二、三句可知，X射线和伽马射线之所以能用来探测和治疗癌症，是因为具有很多能量的x射线和伽马射线能穿透固体。
    根据第五段第五句可知，化学能是在电子重组时产生的。

  • 第14题：

    共用题干
    Electromagnetic Energy
    1 White light seems to be a combination of all colors.The energy that comes from a source of light is not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy day it is possible to get a sunburn even though you feel cool.Visible light and the kinds of energy that produce warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles from the earth.Yet we can use energy from the sun because electromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals travel from transmitters to receivers as low-energy electromagnetic waves.Infrared（红外线的）radiation is an electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light have more energy than waves of radio,television,or radar.Ultraviolet rays（紫外线）and X-rays are electromagnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating buildings. Sunlight and electric lights are part of our requirements for normal living.Ultraviolet radiation is useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel through solid objects. They can be used to detect and treat cancer.X-rays are used in industry to find hidden cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the theory was proposed , nuclear energy was harnessed（利用）by man.Chemical energy comes from electron （电子）rearrangement.Nuclear energy comes from a change in the nucleus of an atom.Compared with chemical reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of'power to generate electricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better methods of obtaining and using energy.

    Paragraph 4______
    A:Nuclear Reactions as the Lasting Source of the Sun's Energy
    B:The Most Important Source of Energy
    C:Types of Electromagnetic Energy
    D:The Machines Used for Energy Generation
    E:Seeking New Sources of Energy
    F:The Use of Ultravio1et Radiation in Medicine

    答案：B
    解析：
    通读文章可知，第三段第一句是段落主题句，紧接着围绕第一句进行了具体阐述，根据第一句中出现的“types of electromagnetic energy”可知，第三段主要讲述几种不同种类的电磁能，应选择C项。
    根据第四段第一、二句可知，我们通常用电来生成电磁能，使用的很多能源都来自太阳。紧接着又表明，水能源于来自太阳的热能，煤储存的能量也是来自太阳。因此不难得出，第四段讲的是能量最重要的来源，即太阳。
    第五段开头提到太阳能的来源仍是个谜，随后对此进行了分析，最后得出太阳能来自核反应释放的能量。由此可知，第五段主要讲的是，氢原子转变为氦原子的核反应释放的能量是太阳能的来源。几个选项中只有A项提到核反应是太阳能的持久来源，因此选择A项。
    通读文章可知，第六段的最后一句是主题句。这句话的大意是：科学家正继续在寻找更好的新方法来获取并使用能源。几个选项中只有E项与之契合，因此选择E项。
    根据第一段第四句可知，你即便在感到凉爽的阴天，也有可能被阳光灼伤，因此选择B项。
    根据第三段第三、四句可知，红外线是电磁波，当它被物质吸收时，会产生能量。
    根据第三段倒数第二、三句可知，X射线和伽马射线之所以能用来探测和治疗癌症，是因为具有很多能量的x射线和伽马射线能穿透固体。
    根据第五段第五句可知，化学能是在电子重组时产生的。

  • 第15题：

    共用题干
    Electromagnetic Energy

    1 White light seems to be a combination of all colors.The energy that comes from a source of light is
    not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy
    day it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce
    warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles away from the earth.Yet we can use energy from the sun because elec-
    tromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signals
    travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an
    electromagnetic wave.When it is absorbed by matter,heat is produced.Waves of infrared and visible light
    have more energy than waves of radio , television , or radar. Ultraviolet rays（紫外线）and X-rays are electro-
    magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating
    buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is
    useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right
    through solid objects.They can be used to detect and treat cancer. X-rays are used in industry to find hidden
    cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the
    sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is
    trapped behind dams and then used to operate electric generators.Other generators are powered by coal,but
    the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If
    the.sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with
    electromagnetic radiation led to the theory that mass can be converted into energy.About forty years after the
    theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron
    （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi-
    cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that
    the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec-
    tncity.It is also being used to operate engines in large ships.Scientists continue to seek new and better
    methods of obtaining and using energy.

    Visible light that produces warmth is an example of______________.
    A:electromagnetic energy
    B:electromagnetic energy travels through space
    C:came from the sun
    D:when a change in the nucleus of an atom takes place
    E:when the sunrays are fierce
    F:chemical energy is generated

    答案：A
    解析：
    第三段的第一句为主题句，意为：许多其他种类的能量也是不同类型的电磁能。该段列举了电磁能的具体例子，C项“Types of Electromagnetic Energy（电磁能的类型）”与主题句意思吻合，故选C。
    第四段的第二句为主题句，意为：我们的能量大多来自太阳。B项“The Most ImportantSource of Energy（最重要的能量来源）”与主题句意思吻合，故选B。
    第五段的最后一句为主题句，意为：我们现在相信太阳的能量来自核反应，在此过程 中，氢转变为氦。A项“Nuclear Reactions as the Lasting Source of the Sun ' s Energy（核反应是太阳能最持久的来源）”与主题句意思吻合，故选A。
    第六段的最后一句为主题句，意为：科学家仍在继续寻找获取和使用能量的新的、更好 的方法。E项“Seeking New Sources of Energy（寻找新的能源）”与主题句意思吻合，故选E。
    第一段的最后一句指出，“可见光和其他能产生热量和造成晒伤的能量都是电磁能的例子”。故选A。
    第二段的第二句指出，“我们能使用太阳能，因为电磁能可以在太空中穿梭”。故选B。
    第四段的最后一句指出，“其他的发电机靠煤炭驱动，但是，煤炭中储存的能量也来自 于太阳”。C项中的“came from the sun（来自太阳）”与原句意思相符，故选C。
    第五段的第五句指出，化学能来自于电子重组。故选F。第4部分：阅读理解第一篇 本文的主要内容是建筑工程师研究世贸大厦遗址及其周围幸存的建筑以设计出能够抵杭恐 怖袭击和爆炸的建筑。

  • 第16题：

    共用题干
    Learn about Light
    1 .Ancient civilizations were amazed by the existence of light for thousands of years. The Greek philosophers believed that light was made up of countless,tiny particles that enter the human eye and create what we call vision. However,Empedocles and a Dutch scientist named Christian Huygens believed that light was like a wave. According to them,light spread out and travelled like a straight line. This theory was accepted during the 19th century.
    2 .In 1905,Albert Einstein published a research paper in which he explained what is re-ferred to as the photoelectric effect. This theory explains that particles make up light.The particles Einstein was referring to are weightless bundles（束）of electromagnetic（电磁）energy called photons（光子）.Today,scientists agree that light has a dual（二重）nature一it is part particle and part wave. It is a form of energy that allows us to see things around us.
    3 .Things that give off light are known as sources of light. During the day,the primary source of light is the sun. Other sources of light include stars,flames,flashlights,street lamps and glowing gases in glass tube.
    4 .When we draw the way light travels we always use straight lines. This is because nor-mally light rays travel in a straight line. However,there are some instances that can change the path and even the nature of light. They are reflection,absorption,interference（干扰）, etc.
    5 .Physicists have attempted to measure the speed of light since the early times. In 1849, Hippolyte Fizeau conducted an experiment by directing a beam of light to a mirror located kilometers away and placed a rotating cogwheel（旋转齿轮）between the beam and the mirror. From the rate of rotation of the wheel,number of wheel's teeth and distance of the mirror,he was able to calculate that the speed of light is 313 million meters per second. In a vacuum（真空）,however,the speed of light is 299,792,458 meters per second. This is about a million times faster than the speed of an airplane.

    Paragraph 3______
    A: How Is the Nature of Light Explained Today?
    B: What Are Sources of Light?
    C: How Did Physicists Measure the Speed of Light?
    D: How Does Light Travel?
    E: How Did People Think of Light Years Ago?
    F: What Causes a Shadow?

    答案：B
    解析：
    该概括大意与完成句子所选的阅读材料为记述文，段落主题相对于论述文而言较松散，因此记述文中的段落大意往往需要考生根据自己的理解而归纳概括出来。解答概括大意题的技巧往往派不上用场。第二段主要讲述现代科学家认同了爱因斯坦的光电效应理论。因此可以判断A选项“当今人们如何解释光的性质”正确。
    第三段第一句“Things that give off light are known as sources of light.”就点明主旨，发光的物体是光源。所以B选项“什么是光源？”正确。
    第四段主要讲述光传播的问题，所以D选项“光是如何传播的”正确。
    第五段的关键字是speed of light，光速。所以C选项“物理学家如何测量光的速度”正确。
    题干意为“人们可以看见物体是因为光……。“从第二段最后一句可知，人们看见物体是因为光是一种能量。所以F项a form of energy正确的。
    题干意为“星星、火焰、手电筒都是……的例子。”第三段“Other sources of light include stars , flames , flashlights...”说明，这些都是光源的例子。所以A选项sourcesof light是正确的。
    题干意为“某些情况下，如反射和吸收可以改变……。”第四段中“there are some instances that can change the path and even the nature of light.They are reflection,ab-sorption , interference , etc.”这说明有一些情况可以改变光的路径。所以C选项the path of light是正确的。
    题干意为“Hippolyte Fizeau做了一个刚试……的实验。”文中最后一段 “Hippolyte Fizeau conducted an experiment by directing a beam of light to a mirror...he was able to calculate that the speed of light...”可知Hippolyte Fizeau通过实验计算出了光速。所以B选项是正确的。

  • 第17题：

    共用题干
    第三篇

    Small but Wise

    On December 14,NASA blasted a small but mighty telescope into space.The telescope is called WISE
    and is about as wide around as a trashcan.Don't let its small size fool you:WISE has a powerful digital
    camera,and it will be taking pictures of some of the wildest objects in the known universe,including
    asteroids,faint stars,blazing galaxies and giant clouds of dust where planets and stars are born.
    "I'm very excited because we're going to be seeing parts of the universe that we haven't seen be-
    fore,"said Ned Wright,a scientist who directs the WISE project.
    Since arriving in space,the WISE telescope has been circling the Earth,held by gravity in a polar orbit
    (this means it crosses close to the north and south poles with each lap).Its camera is pointed outward,away
    from the Earth,and WISE will snap a picture of a different part of the sky every 11 minutes.After six months
    it will have taken pictures across the entire sky.
    The pictures taken by WISE won't be like everyday digital photographs,however. WISE stands for
    "Wide-field Infrared Survey Explorer".As its name suggests,the WISE camera takes pictures of features
    that give off infrared radiation.
    Radiation is energy that travels as a wave.Visible light,including the familiar spectrum of light that be-
    comes visible in a rainbow,is an example of radiation.When an ordinary digital camera takes a picture of a
    tree,for example,it receives the waves of visible light that are reflected off the tree.When these waves enter
    the camera through the lens,they're processed by the camera,which then puts the image together.
    Waves of infrared radiation are longer than waves of visible light,so ordinary digital cameras don't see
    them,and neither do the eyes of human beings.Although invisible to the eye,longer infrared radiation can
    be detected as warmth by the skin.
    That's a key idea to why WISE will be able to see things other telescopes can't. Not everything in the
    universe shows up in visible light.Asteroids,for example, are giant rocks that float through space一but they
    absorb most of the light that reaches them.They don't reflect light,so they're difficult to see.But they do
    give off infrared radiation,so an infrared telescope like WISE will be able to produce images of them.During
    its mission WISE will take pictures of hundreds of thousands of asteroids.
    Brown dwarfs are another kind of deep-space objects that will show up in WISE's pictures.These ob-
    jects are "failed" stars一which means they are not massive enough to jump-start the same kind of reactions
    that power stars such as the sun.Instead,brown dwarfs simply shrink and cool down.They're so dim that
    they're almost impossible to see with visible light,but in the infrared spectrum they glow.

    It is true that infrared radiation_________.
    A:is not detectable to humans
    B:looks brighter than visible light
    C:is visible light reflected off an object
    D:has longer waves than those of visible light

    答案：D
    解析：
    由文章前两段内容可知，这个太空望远镜携带的数码相机可以拍到我们未知的宇宙里 的众多物体，它将使人类看到宇宙中的未知部分，故选C。
    这个太空望远镜其实是个广视场红外线探测器（Wide-field Infrared Survey Explorer)，它 能拍到产生红外线辐射的物体，故选B。
    由文章第六段内容可知，红外线辐射波比可见光的波长更长，因此普通的相机和肉眼 都是看不到它们的，但是红外线波可由皮肤感知，故本题选D。
    由文章第七段第二、三句“Not everything in the universe shows up in visible light.Asteroids , for example...”可知，不是所有的物体都是以可见光的形式被发现的，小行星就是一 例，它们发出红外线，太空望远镜WISE可以感测到，故选C。
    由最后一段内容可知，棕矮星能够被WISE探测到，说明它们发射的光不是可见光，而 是红外线波，故选A。

  • 第18题：

    共用题干
    Electromagnetic Energy

    1 White light seems to be a combination of all colors.The energy that comes from a source of light is
    not limited to the kind of energy you can see.Heat is given off by a flame or an electric light.On a cloudy
    day it is possible to get a sunburn even though you feel cool.Visible light and the kind of energy that produce
    warmth and sunburn are examples of electromagnetic energy.
    2 The sun is 93 million miles away from the earth.Yct we can use energy from die sun because elec-
    tromagnetic energy travels through space.
    3 Many other kinds of energy are also types of electromagnetic energy.Radio,television,and radar signais
    travel from transmitters to receivers as low-energy electromagnetic waves. Infrared（红外线的）radiation is an
    electromagnetic wave.When it is absorbed by matter,heat is produced.Wayes of infrared and visible light
    have more energy than waves of radio,television,or radar. Ultraviolet rays（紫外线）and X-rays are eleetro-
    magnetic waves with even greater amounts of energy.Infrared radiation is used in cooking food and heating
    buildings.Sunlight and electric lights are part of our requirements for normal living. Ultraviolet radiation is
    useful in killing certain disease organisms.X-rays and gamma rays have so much energy that they travel right
    through solid objects.They can be used to detect and treat cancer。 X-rays are used in industry to find hidden
    cracks in metal,and in medicine to reveal broken bones.
    4 Usually we use electricity to generate electromagnetic energy.The source of most of our energy is the
    sun.Heat from the sun causes water to evaporate.When the water falls to the earth as rain,some of it is
    trapped behind dams and then used to operate electric generators,Other generators are powered by coal,but
    the energy stored in coal came from the sun,too.
    5 Until recently,the source of the tremendous amount of energy given off by the sun was a puzzle.If
    the sun depended on chemical reactions,it would have used up all its energy long ago.Experiments with
    electromagnetic radiation led to the theory that mass can be converted into energy．入bout forty years after the
    theory was proposed , nuclear energy was harnessed（利用）by man. Chemical energy comes from electron
    （电子）rearrangement. Nuclear energy comes from a change in the nucleus of an atom. Compared with chemi-
    cal reactions,nuclear reactions release millions of times more energy per pound of fuel.We now believe that
    the sun's energy comes from the nuclear reactions in which hydrogen is changed into helium（氦）.
    6 Nuclear energy is beginning to compete with coal as an economical source of power to generate elec-
    tricity.It is also being used to operate engines in large ships.Scientists continue to seek new and better
    methods of obtaining and using energy.

    Visible light that produces warmth is an example of _______________.
    A:electromagnetic energy
    B:electromagnetic energy travels through space
    C:came from the sun
    D:when a change in the nucleus of an atom takes place
    E:whlen the sunrays are fierce
    F:chemical energy is generated

    答案：A
    解析：
    第三段的第一句为主题句，意为：许多其他种类的能量也是不同类型的电磁能。该段 列举了电磁能的具体例子，C项“Types of Electromagnetic Energy（电磁能的类型）”与主题句意 思吻合，故选C。
    第四段的第二句为主题句，意为：我们的能量大多来白太阳。B项“The Most Important Source of Energy（最重要的能量来源）”与主题句意思吻合，故选B。
    第五段的最后一句为主题句，意为；我们现在相信太阳的能量来自核反应，在此过程 中，氢转变为氦。A项“Nuclear Reactions as the Lasting Source of the Sun' s Energy（核反应是太 阳能最持久的来源）”与主题句意思吻合，故选A。
    第六段的最后一句为主题句，意为：科学家仍在继续寻找获取和使用能量的新的、更好 的方法。E项“Seeking New Sources of Energy（寻找新的能源）”与主题句意思吻合，故选E。
    第一段的最后一句指出，“可见光和其他能产生热量和造成晒伤的能量都是电磁能的 例子”。故选A。
    第二段的第二句指出，“我们能使用太阳能，因为电磁能可以在太空中穿梭”。故选B。
    第四段的最后一句指出，“其他的发电机靠煤炭驱动，但是，煤炭中储存的能量也来自 于太阳”。C项中的“came from the sun (来自太阳）”与原句意思相符，故选C。
    第五段的第五句指出，化学能来自于电子重组。故选F。第4部分：阅读理解第一篇 本文介绍了引起食物中毒的原因及食物中毒的预防和治疗处理措施。

  • 第19题：

    单选题
    All of the following information concerning lighted aids to navigation may be read directly from the Light List EXCEPT the（）.
    A

    location

    B

    height of light above water

    C

    luminous range

    D

    light characteristics


    正确答案： D
    解析： 暂无解析

  • 第20题：

    单选题
    An alternating light（）.
    A

    shows a light with varying lengths of the lighted period

    B

    shows a light that changes color

    C

    marks an alternate lesser-used channel

    D

    is used as a replacement for another light


    正确答案： C
    解析： 暂无解析

  • 第21题：

    单选题
    If several fixed navigational lights are visible at the same time，each one may be positively identified by checking all of the following EXCEPT what against the Light List?（）
    A

    Rhythm

    B

    Period

    C

    Intensity

    D

    Color


    正确答案： D
    解析： 暂无解析

  • 第22题：

    单选题
    You have berthed in a area with other tank vessels. What signal is displayed by a vessel to indicate it is transferring flammable or combustible liquid cargo?（）.
    A

    A flashing yellow light

    B

    A red light visible all around the horizon

    C

    A green light visible all around the horizon

    D

    An illuminated red and yellow caution flag


    正确答案： D
    解析： 暂无解析

  • 第23题：

    单选题
    A head on situation shall be deemed to exist at night when a power-driven vessel sees another power-driven vessel ahead and （）.
    A

    one sidelight and the masthead light are visible

    B

    the vessels will pass closer than half a mile

    C

    both vessels sound one prolonged blast

    D

    both sidelights and masthead light(s) are visible


    正确答案： D
    解析： 暂无解析

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