Recent research had claimed that an excess of positive ions (离子) in the air can have an ill-effect on people's physical or psychological health. What are positive ions? Well, the air is full of ions, electrically charged particles, and generally there is
题目
Recent research had claimed that an excess of positive ions (离子) in the air can have an ill-effect on people's physical or psychological health. What are positive ions? Well, the air is full of ions, electrically charged particles, and generally there is a rough balance between the positive and the negative charges. But sometimes this balance becomes disturbed and a larger proportion of positive ions are found. This happens naturally before thunderstorms, earthquakes or when winds are blowing in certain countries. Or it can be caused by a build-up of static electricity indoors from carpets or clothing made of man-made fibers, or from TV sets, duplicators or computer display screens.
When a large number of positive ions are present in the air many people experience unpleasant effects such as headaches, fatigue, irritability, and some particularly sensitive people suffer nausea (恶心) or even mental disturbance. Animals are also found to be affected, particularly before earthquakes; snakes have been observed to come out of hibernation(冬眠), rats to flee from their burrows, dogs howl and cats jump about unaccountably. This has led the US Geographical Survey to fund a network of volunteers to watch animals in all effort to foresee such disasters before they hit vulnerable areas such as California.
Conversely, when large numbers of negative ions are present, then people have a feeling of well-being. Natural conditions that produce these large amounts are near the sea, close to waterfalls or fountains, or in any place where water is sprayed, or forms a spray. This probably accounts for the beneficial effect of a holiday by the sea, or in the mountains with tumbling streams or waterfalls.
To increase the supply of negative ions indoors, some scientists recommend the use of ionizers : small portable machines which generate negative ions. They claim that ionizers not only clean and refresh the air but also improve the health of people sensitive to excess positive ions. Of course, there are the detractors, other scientists, who dismiss such claims and are skeptical about negative/positive ion research. Therefore people can only make up their own minds by observing the effects on themselves, or on others, of a negative rich or poor environment.
After all, it is debatable whether depending on seismic readings to anticipate earthquakes is more effective than watching the cat.
According to the passage, static electricity can be caused by
A．using home-made electrical goods.
B．wearing clothes made of natural materials.
C．walking on artificial floor coverings.
D．copying TV programs on a computer.
相似考题
更多“Recent research had claimed that an excess of positive ions (离子) in the air can have an ill-effect on people's physical or psychological health. What are positive ions? Well, the air is full of ions, electrically charged particles, and generally there is ”相关问题
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第1题：
From what you _____, you can understand why an object weighs less in water than in air.
A、had learnt
B、will learn
C、have learnt
D、can learn
参考答案：C
-
第2题：
共用题干
第二篇
As we have seen,the focus of medical care in our society has been shifting from curing disease to preventing disease一especially in terms of changing our many unhealthy behaviors,such as poor eating habits,smoking,and failure to exercise.The line of thought involved in this shift can be pursued further. Imagine a person who is about the right weight , but does not eat very nutritious（有营养的）foods , who feels OK but exercises only occasionally , who goes to work every day , but is not an outstanding worker,who drinks a few beers at home most nights but does not drive while drunk, and who has no chest pains or abnormal blood counts,but sleeps a lot and often feels tired.This person is not ill.He may not even be at risk for any particular disease.But we can imagine that this person could be a lot healthier.
The field of medicine has not traditionally distinguished between someone who is merely "not ill" and someone who is in excellent health and pays attention to the body's special needs.Both types have simply been called "well".In recent years,however,some health specialists have begun to apply the terms "well" and "weilness" only to those who are actively striving to maintain and improve their body's condition.Most importantly,perhaps,people who are well take active responsibility for all matters related to their health.Even people who have a physical disease or handicap（缺陷）may be "well" ,in this new sense,if they make an effort to maintain the best possible health they can in the face of their physical limitations."Wellness" may perhaps best be viewed not as a state that people can achieve,but as an ideal that people can strive for. People who are well are likely to be better able to resist disease and to fight disease when it strikes.And by focusing attention on healthy ways of living,the concept of weilness can have a beneficial impact on the way in which people face the challenges of daily life.According to the second paragraph about the traditional care,which statement is true?
A:if the person does not have' any unhealthy living habits,he is considered "well".
B:If the person does not have any psychological disease,he is considererd "well".
C:If the person could be able to handle his daily routines,he is considererd "well".
D:If the nerson could be free from any kind of disease.he is considererd "well".答案：D解析：细节题。根据第一段第一句“…the focus of medical care in our society has been-shifting from curing disease to preventing disease一especially in terms of changing our many unhealthy behaviors...”可知，今天医疗保健的焦点已经从疾病治疗转移到疾病预防上来，尤其体现在改变我们不健康的行为上。因此，选项C“改变人们不良的生活习惯”与文章相符。
主旨题。由第一段倒数三句“This person is not ill.He may not even be at risk for any particular disease.But we can imagine that this person could be a lot healthier.”可知，这个人虽然有一些不良习惯和不适的症状，但是没有患病，甚至也没有患病的风险，然而，我们可以想象这个人本来可以更健康。由此可知，选项A“健康不仅仅是没有病”符合文意。
推断题。根据第二段第一、二句“The field of medicine has not traditionally distinguished between someone who is merely'not ill'and someone who is in excellent health and pays attention to the body's special needs.Both types have simply been called 'well'.”可知，传统上，医学界把没病的人和十分健康的人都称作“身体良好的人”。因此，选项D“没病就是身体良好”符合文意。
细节题。根据第二段的倒数第三句“'Weilness' may perhaps best be viewed not as a state that people can achieve,but as an ideal than people can strive for.”可知，“健康”并不是我们可能获得的一种健康的状态，而是一种我们要努力争取的理念。因此选项B 符合题意。
主旨题。文章第一段提出医疗保健的焦点由疾病治疗转到疾病预防；第二段首先阐述了传统医疗保健观点和现在医疗保健观点对健康的定义，之后依据现在医疗保健观点给健康作出了更积极的定义，可见选项C符合题意。选项A"旨在批判医疗保健的传统观点”是对原文的曲解，原文只是提出新的观点，并没有批驳传统的医疗保健；选项B"旨在对比传统和现在医疗保健观、点的不同”不是本文的写作目的，比较的目的在于强调现在的医疗观；选项D"旨在告诉我们医疗保健的重要性”文中并未提及。 -
第3题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers. Now,in test flights over the Rocky
Mountains , NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin. In December 1 997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts.“It is the only antidote（对策）for this sort of thing,”says Rod Bogue,project manager at NASA's Dryden Flight
Research Center in Edwards,California.
The centre's new turbulence detector is based on lidar,or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect.The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩）in rough air,their speed of approach increases or decreases rapidly .The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into disturbed air over the mountain ridges（山脉）near Pueblo , Colorado. The lidar detector spotted turbulence between 3 and 8 kilometers ahead,and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had“a comfortable amount of time”to fasten his seatbelt. The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.What does“clear-air turbulence”in Paragraph 1 probably mean?
A: A not very rough storm.
B: Unexpected disturbed air.
C: A kind of visible storm.
D: A storm over mountain ridges.答案：B解析：本题问的是“clear-air turbulence”在文中指什么？turbulence的意思就是湍流，根据第二段第二句的说法，clear-air turbulence指的是雷达无法测到的一种turbulence，所以选项B为正确答案。
该题问的是1997年12月联合航空公司的一架班机在碰到这种气流后，遭遇了什么结果？原文讲到造成一人死亡，多人受伤，据此判断，损失惨重，故选C。
此题问气流探测器通过测量什么来判断它的激烈程度？第四段最后一句说“The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.”所以选项 D为正确答案。
此题要求根据第五段的信息判断下面哪句话是正确的。显然，选项A符合原文的意思，为正确答案。
此题是根据最后一段的第二句“The researchers are planning to improve the lidar's range with a more powerful beam.”出的题，这句的意思是说，研究人员正计划采用功能更强大的光束来提高雷达的侧定范围。据此可以判断，雷达尚需改进，故A为正确答案。 -
第4题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers. Now,in test flights over the Rocky
Mountains , NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin. In December 1 997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts.“It is the only antidote（对策）for this sort of thing,”says Rod Bogue,project manager at NASA's Dryden Flight
Research Center in Edwards,California.
The centre's new turbulence detector is based on lidar,or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect.The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩）in rough air,their speed of approach increases or decreases rapidly .The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into disturbed air over the mountain ridges（山脉）near Pueblo , Colorado. The lidar detector spotted turbulence between 3 and 8 kilometers ahead,and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had“a comfortable amount of time”to fasten his seatbelt. The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.The turbulence detector can tell the severity of the turbulence by measuring_______.
A:.the speed of the plane
B:.the speed of the light
C:.the number of particles in the air
D:.the changes of the particles' speed答案：D解析：本题问的是“clear-air turbulence”在文中指什么？turbulence的意思就是湍流，根据第二段第二句的说法，clear-air turbulence指的是雷达无法测到的一种turbulence，所以选项B为正确答案。
该题问的是1997年12月联合航空公司的一架班机在碰到这种气流后，遭遇了什么结果？原文讲到造成一人死亡，多人受伤，据此判断，损失惨重，故选C。
此题问气流探测器通过测量什么来判断它的激烈程度？第四段最后一句说“The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.”所以选项 D为正确答案。
此题要求根据第五段的信息判断下面哪句话是正确的。显然，选项A符合原文的意思，为正确答案。
此题是根据最后一段的第二句“The researchers are planning to improve the lidar's range with a more powerful beam.”出的题，这句的意思是说，研究人员正计划采用功能更强大的光束来提高雷达的侧定范围。据此可以判断，雷达尚需改进，故A为正确答案。 -
第5题：
共用题干
Women with AIDS
For a long time women with HIV were ignored because the focus was totally on HIV men.The gay community was very much in sight and vocal and successfully got support for its cause.Now we are rapidly approaching the point where about one haff of all AIDS cases in the. world are women. But no one is taking this dangerously high level of infection among women seriously enough.
Women usually have a worse time dealing with HIV than men do.In most cases,the woman is taking care of children as well as her sick partner. She may not even have time to take care of herself. The HIV-positive woman ends up shouldering the family as well as her own personal problems. Men,however,are usually the ones who have insurance income and access to doctors.They get care.Women often do not.
The discrimination against HIV-positive women is simply terrible.They are likely to be more inactive than men in the home and workplace because too many people think that women are the cause of the disease.This is not at all true.They get it from a man.They don't just simply have HIV.Of course,there's a social discrimination against all people with HIV.They are scared that other people will know they are HJV-positive and that they will,therefore be discriminated against. For example,it's very difficult for people with HIV to travel.They are not allowed to enter many countries,including the United States,China and Russia.
The biggest difficulty an HIV-positive woman must face is the isolatjon.Once the woman knows she's HIV-positive,she lives in fear that other people will find out.She's so frightened she will go into hiding,into an isolated place by herself. It's not at all uncommon to meet a woman who has been HIV-positive for nearly 10 years and has never told anyone,except her doctor. And the resulting stress is enough to make her sick.But HIV-positive women who get support,who can discuss their trouble and then do something about it一whether that means taking better care of themselves or going to the United Nations to struggle for their rights一are likely to live longer. Active women don't die out of shame in a corner. This happens to too many HIV-positive women.Isolation is the biggest difficulty for HIV-positive women.
A:Right
B:Wrong
C:Not mentioned答案：A解析：第一段第三句讲到“全球艾滋病病例中的一半都是女性”，因此本句表述是正确的。
第一段最后一句讲到“no one is taking this dangerously high level of infection among women seriously enough"，即没人认真对待女性中危险的高感染率。因此本句的表述是错误的。
虽然文章第三段最后一句提到很多国家不允许携带HIV病毒的人入境，如美国、中国和俄罗斯，却并没有说这些国家的艾滋病感染者最多。因此选项C是正确的。
文章第三段描述了患艾滋病的女性所受的歧视，但是中间也提到“there's a social discrimination against all people with HIV"，所以应该是所有患艾滋病的人都会受到社会歧视。本句陈述是错误的，选择选项B。
最后一段第一句就说："The biggest difficulty an HIV-positive woman must face is the isolation.”因而本句表述是正确的，选择选项A。
文章最后一段讲到那些得到支持并且能同他人讨论自己的问题，从而采取对策的HIV呈阳性的女人可能会活得更长。对具备这些特质的女人，作者在后文中称呼她们为“active women"。因此该句表述是正确的，选择选项A。
文章中并没有直接明说，但是从最后一段作者对消极应对艾滋病的种种危害的描述来看，他是鼓励患艾滋病的女性勇敢地告诉他人以减轻自己的压力，更好地治疗。因此选项A是正确的。 -
第6题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers.Now,in test flights over the Rocky Mountains, NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin.In December 1997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts."It is the only antidote（对 策）for this sort of thing,"says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards,California.
The Center's new turbulence detector is based on lidar,or laser-radar.Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air.The technique depends on the Doppler Effect（多普勒效应）.The wavelength of the light shifts according to the speed at which the particles are approaching.In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩） in rough air,their speed of approach increases or decreases rapidly.The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into、 disturbed air over the mountain ridges（山脉）near Pueblo , Colorado.The lidar detector spotted turbulence between 3 and 8 kilometers ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had"a comfortable amount of time"to fasten his seatbelt.The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.What does"clear-air turbulence"in Paragraph 1 probably mean?
A:A not very rough storm.
B:Unexpected disturbed air.
C:A kind of visible storm.
D:A storm over mountain ridges.答案：B解析：根据第二段第三句，再结合上文可知，clear-air turbulence指的是第二段第三段中的“unexpectedrough air"，又由于disturbed与rough意义相近，故选B。
根据二段最后一句可知，1997年12月份的晴空湍流导致1人死亡、100人受伤，可以说是造成了很多伤亡。
根据第四段最后一句可知，晴空湍流的强度与微粒速度的变化有关。
根据第五段最后一句可知，激光雷达探测器能够探测到前方3千米到8千米之间的晴空湍流，并且预测的晴空湍流的强度和持续时间与真实情况相符。这说明激光雷达探测器能成功地预测晴空湍流。
根据最后一段第二句可知，研究人员正计划改善激光雷达探测器，准备使用更强的电脉冲来提升激光雷达探测器的探测范围。 -
第7题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers.Now,in test flights over the Rocky Mountains, NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin.In December 1997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts."It is the only antidote（对 策）for this sort of thing,"says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards,California.
The Center's new turbulence detector is based on lidar,or laser-radar.Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air.The technique depends on the Doppler Effect（多普勒效应）.The wavelength of the light shifts according to the speed at which the particles are approaching.In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩） in rough air,their speed of approach increases or decreases rapidly.The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into、 disturbed air over the mountain ridges（山脉）near Pueblo , Colorado.The lidar detector spotted turbulence between 3 and 8 kilometers ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had"a comfortable amount of time"to fasten his seatbelt.The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.We can infer from the fifth paragraph that____＿.
A:the lidar detector can successfully forecast turbulence
B:researchers are not sure about the effectiveness of the lidar detector
C:passenger planes will be used in further experiments
D:no more test flights are needed答案：A解析：根据第二段第三句，再结合上文可知，clear-air turbulence指的是第二段第三段中的“unexpectedrough air"，又由于disturbed与rough意义相近，故选B。
根据二段最后一句可知，1997年12月份的晴空湍流导致1人死亡、100人受伤，可以说是造成了很多伤亡。
根据第四段最后一句可知，晴空湍流的强度与微粒速度的变化有关。
根据第五段最后一句可知，激光雷达探测器能够探测到前方3千米到8千米之间的晴空湍流，并且预测的晴空湍流的强度和持续时间与真实情况相符。这说明激光雷达探测器能成功地预测晴空湍流。
根据最后一段第二句可知，研究人员正计划改善激光雷达探测器，准备使用更强的电脉冲来提升激光雷达探测器的探测范围。 -
第8题：
One of the main advantages of a graphite-furnace atomizer is that（）
- A、It requires only very small quantities of a sample
- B、It requires metal.ions in aqueous solution
- C、It does not produce background emission like a flame
- D、It does not get hot like a flame
正确答案:A -
第9题：
单选题According to a recent research， the old are more than twice as likely to have a positive attitude to life___ the young.Aas
Bthan
Cwhile
Duntil
正确答案： D解析： -
第10题：
单选题Recent studies have suggested that weight training _____.Ahas become an essential part of people’s life
Bmay well affect the health of the trainees
Cwill attract more people in the days to come
Dcontributes to health improvement as well
正确答案： D解析：
细节题。依据第二段第二句指出，近几年来，有证据表明，原本设计为增进肌肉力量和耐力的举重锻炼对人的健康也有好处，这与D项相符，故D为答案。 -
第11题：
单选题Which of the following statements describes the function of an air compressor intake filter?（）AProtects against suction valve float
BProvides a positive pressure on the air inlet valves
CPrevents lubricating oil contamination of the compressed air supply
DProtects against the damaging effects of airborne solid particles
正确答案： C解析： 暂无解析 -
第12题：
单选题One of the main advantages of a graphite-furnace atomizer is that（）AIt requires only very small quantities of a sample
BIt requires metal.ions in aqueous solution
CIt does not produce background emission like a flame
DIt does not get hot like a flame
正确答案： D解析： 暂无解析 -
第13题：
Health implies more than physical fitness. It also implies mental and emotional well-being. An angry, frustrated, emotionally21 person in good physical condition is not 22healthy. Mental health, therefore, has much to do23 how a person copes with the world as s/he exists. Many of the factors that 24 physical health also affect mental and emotional well-being.
Having a good self-image means that people have positive25 pictures and good, positive feelings about themselves, about what they are capable26, and about the roles they play. People with good self-images like themselves, and they are27 like others. Having a good self-image is based 28 a realistic, as well as positive, or optimistic29of one’s own worth and value and capabilities.
Stress is an unavoidable, necessary, and potentially healthful 30 of our society. People of all ages 31 stress. Children begin to32stress during prenatal development and during childbirth. Examples of stress-inducing 33 in the life of a young person are death of a pet, pressure to 34 academically, the divorce of parents, or joining a new youth group. The different ways in which individuals35 to stress may bring healthful or unhealthy results. One person experiencing a great deal of stress may function exceptionally well 36 another may be unable to function at all. If stressful situations are continually encountered, the individual’s physical, social, and mental health are eventually affected.
Satisfying social relations are vital to37 mental and emotional health. It is believed that in order to38, develop, and maintain effective and fulfilling social relationships people must 39 the ability to know and trust each other, understand each other, influence, and help each other. They must also be capable of40 conflicts in a constructive way.
21.
[A] unstable
[B] unsure
[C] imprecise
[D] impractical
正确答案：A
21. A
An angry, frustrated, emotionally unstable person in good physical condition is not necessarily healthy.一个易怒的，情绪沮丧的，感情不稳定但是体格很好的人，未必是健康的。 -
第14题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers. Now,in test flights over the Rocky
Mountains , NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin. In December 1 997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts.“It is the only antidote（对策）for this sort of thing,”says Rod Bogue,project manager at NASA's Dryden Flight
Research Center in Edwards,California.
The centre's new turbulence detector is based on lidar,or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect.The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩）in rough air,their speed of approach increases or decreases rapidly .The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into disturbed air over the mountain ridges（山脉）near Pueblo , Colorado. The lidar detector spotted turbulence between 3 and 8 kilometers ahead,and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had“a comfortable amount of time”to fasten his seatbelt. The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.We can infer from the fifth paragraph that______.
A: the lidar detector can successfully forecast turbulence
B: researchers are not sure about the effectiveness of the lidar detector
C: passenger planes will be used in further experiments
D: no more test flights are needed答案：A解析：本题问的是“clear-air turbulence”在文中指什么？turbulence的意思就是湍流，根据第二段第二句的说法，clear-air turbulence指的是雷达无法测到的一种turbulence，所以选项B为正确答案。
该题问的是1997年12月联合航空公司的一架班机在碰到这种气流后，遭遇了什么结果？原文讲到造成一人死亡，多人受伤，据此判断，损失惨重，故选C。
此题问气流探测器通过测量什么来判断它的激烈程度？第四段最后一句说“The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.”所以选项 D为正确答案。
此题要求根据第五段的信息判断下面哪句话是正确的。显然，选项A符合原文的意思，为正确答案。
此题是根据最后一段的第二句“The researchers are planning to improve the lidar's range with a more powerful beam.”出的题，这句的意思是说，研究人员正计划采用功能更强大的光束来提高雷达的侧定范围。据此可以判断，雷达尚需改进，故A为正确答案。 -
第15题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers. Now,in test flights over the Rocky
Mountains , NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin. In December 1 997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts.“It is the only antidote（对策）for this sort of thing,”says Rod Bogue,project manager at NASA's Dryden Flight
Research Center in Edwards,California.
The centre's new turbulence detector is based on lidar,or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect.The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩）in rough air,their speed of approach increases or decreases rapidly .The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into disturbed air over the mountain ridges（山脉）near Pueblo , Colorado. The lidar detector spotted turbulence between 3 and 8 kilometers ahead,and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had“a comfortable amount of time”to fasten his seatbelt. The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.In December 1997,a United Airlines flight hit unexpected rough air,_______.
A: causing a lot of damage to the plane
B: throwing its passengers out of the cabin
C: resulting in heavy casualties
D: forcing the pilot to make an emergency landing答案：C解析：本题问的是“clear-air turbulence”在文中指什么？turbulence的意思就是湍流，根据第二段第二句的说法，clear-air turbulence指的是雷达无法测到的一种turbulence，所以选项B为正确答案。
该题问的是1997年12月联合航空公司的一架班机在碰到这种气流后，遭遇了什么结果？原文讲到造成一人死亡，多人受伤，据此判断，损失惨重，故选C。
此题问气流探测器通过测量什么来判断它的激烈程度？第四段最后一句说“The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.”所以选项 D为正确答案。
此题要求根据第五段的信息判断下面哪句话是正确的。显然，选项A符合原文的意思，为正确答案。
此题是根据最后一段的第二句“The researchers are planning to improve the lidar's range with a more powerful beam.”出的题，这句的意思是说，研究人员正计划采用功能更强大的光束来提高雷达的侧定范围。据此可以判断，雷达尚需改进，故A为正确答案。 -
第16题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers. Now,in test flights over the Rocky
Mountains , NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin. In December 1 997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts.“It is the only antidote（对策）for this sort of thing,”says Rod Bogue,project manager at NASA's Dryden Flight
Research Center in Edwards,California.
The centre's new turbulence detector is based on lidar,or laser radar. Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air. The technique depends on the Doppler effect.The wavelength of the light shifts according to the speed at which the particles are approaching. In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩）in rough air,their speed of approach increases or decreases rapidly .The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into disturbed air over the mountain ridges（山脉）near Pueblo , Colorado. The lidar detector spotted turbulence between 3 and 8 kilometers ahead,and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had“a comfortable amount of time”to fasten his seatbelt. The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.The last paragraph tells us,among other things,that_______.
A: the lidar detector needs improvement
B: many airlines are interested in the system
C: passengers often forget to fasten their seatbelts
D: the lidar detector can be used in a wide range of areas答案：A解析：本题问的是“clear-air turbulence”在文中指什么？turbulence的意思就是湍流，根据第二段第二句的说法，clear-air turbulence指的是雷达无法测到的一种turbulence，所以选项B为正确答案。
该题问的是1997年12月联合航空公司的一架班机在碰到这种气流后，遭遇了什么结果？原文讲到造成一人死亡，多人受伤，据此判断，损失惨重，故选C。
此题问气流探测器通过测量什么来判断它的激烈程度？第四段最后一句说“The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.”所以选项 D为正确答案。
此题要求根据第五段的信息判断下面哪句话是正确的。显然，选项A符合原文的意思，为正确答案。
此题是根据最后一段的第二句“The researchers are planning to improve the lidar's range with a more powerful beam.”出的题，这句的意思是说，研究人员正计划采用功能更强大的光束来提高雷达的侧定范围。据此可以判断，雷达尚需改进，故A为正确答案。 -
第17题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers.Now,in test flights over the Rocky Mountains, NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin.In December 1997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts."It is the only antidote（对 策）for this sort of thing,"says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards,California.
The Center's new turbulence detector is based on lidar,or laser-radar.Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air.The technique depends on the Doppler Effect（多普勒效应）.The wavelength of the light shifts according to the speed at which the particles are approaching.In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩） in rough air,their speed of approach increases or decreases rapidly.The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into、 disturbed air over the mountain ridges（山脉）near Pueblo , Colorado.The lidar detector spotted turbulence between 3 and 8 kilometers ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had"a comfortable amount of time"to fasten his seatbelt.The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.The last paragraph tells us,among other things,that____＿.
A:the lidar detector needs improvement
B:many airlines are interested in the system
C:passengers often forget to fasten their seatbelts
D:the lidar detector can be used in a wide range of areas答案：A解析：根据第二段第三句，再结合上文可知，clear-air turbulence指的是第二段第三段中的“unexpectedrough air"，又由于disturbed与rough意义相近，故选B。
根据二段最后一句可知，1997年12月份的晴空湍流导致1人死亡、100人受伤，可以说是造成了很多伤亡。
根据第四段最后一句可知，晴空湍流的强度与微粒速度的变化有关。
根据第五段最后一句可知，激光雷达探测器能够探测到前方3千米到8千米之间的晴空湍流，并且预测的晴空湍流的强度和持续时间与真实情况相符。这说明激光雷达探测器能成功地预测晴空湍流。
根据最后一段第二句可知，研究人员正计划改善激光雷达探测器，准备使用更强的电脉冲来提升激光雷达探测器的探测范围。 -
第18题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers.Now,in test flights over the Rocky Mountains, NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin.In December 1997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts."It is the only antidote（对 策）for this sort of thing,"says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards,California.
The Center's new turbulence detector is based on lidar,or laser-radar.Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air.The technique depends on the Doppler Effect（多普勒效应）.The wavelength of the light shifts according to the speed at which the particles are approaching.In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩） in rough air,their speed of approach increases or decreases rapidly.The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into、 disturbed air over the mountain ridges（山脉）near Pueblo , Colorado.The lidar detector spotted turbulence between 3 and 8 kilometers ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had"a comfortable amount of time"to fasten his seatbelt.The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.In December 1997,a United Airlines flight hit unexpected rough air______.
A:causing a lot of damage to the plane
B:throwing its passengers out of the cabin
C:resulting in heavy casualties
D:forcing the pilot to make an emergency landing答案：C解析：根据第二段第三句，再结合上文可知，clear-air turbulence指的是第二段第三段中的“unexpectedrough air"，又由于disturbed与rough意义相近，故选B。
根据二段最后一句可知，1997年12月份的晴空湍流导致1人死亡、100人受伤，可以说是造成了很多伤亡。
根据第四段最后一句可知，晴空湍流的强度与微粒速度的变化有关。
根据第五段最后一句可知，激光雷达探测器能够探测到前方3千米到8千米之间的晴空湍流，并且预测的晴空湍流的强度和持续时间与真实情况相符。这说明激光雷达探测器能成功地预测晴空湍流。
根据最后一段第二句可知，研究人员正计划改善激光雷达探测器，准备使用更强的电脉冲来提升激光雷达探测器的探测范围。 -
第19题：
共用题干
Please Fasten Your Seatbelts
Severe turbulence（湍流）can kill aircraft passengers.Now,in test flights over the Rocky Mountains, NASA（美国航空航天局）engineers have successfully detected clear-air turbulence up to 10 seconds before an aircraft hits it.
Clear-air turbulence often catches pilots by surprise.Invisible to radar,it is difficult to forecast and can hurl（用力抛出去）passengers about the cabin.In December 1997 , one passenger died and a hundred others were injured when unexpected rough air caused a United Airlines flight over the Pacific to drop 300 meters in a few seconds.
However,passengers can avoid serious injury by fastening their seatbelts."It is the only antidote（对 策）for this sort of thing,"says Rod Bogue, project manager at NASA's Dryden Flight Research Center in Edwards,California.
The Center's new turbulence detector is based on lidar,or laser-radar.Laser pulses are sent ahead of the plane and these are then reflected back by particles in the air.The technique depends on the Doppler Effect（多普勒效应）.The wavelength of the light shifts according to the speed at which the particles are approaching.In calm air,the speed equals the plane's airspeed.But as the particles swirl（打漩） in rough air,their speed of approach increases or decreases rapidly.The rate of change in speed corresponds to the severity（激烈程度）of the turbulence.
In a series of tests that began last month,a research jet flew repeatedly into、 disturbed air over the mountain ridges（山脉）near Pueblo , Colorado.The lidar detector spotted turbulence between 3 and 8 kilometers ahead, and its forecasts of strength and duration corresponded closely with the turbulence that the plane encountered.
Bogue says that he had"a comfortable amount of time"to fasten his seatbelt.The researchers are planning to improve the lidar's range with a more powerful beam.The system could be installed on commercial aircraft in the next few years.The turbulence detector can tell the severity of the turbulence by measuring______.
A:the speed of the plane
B:the speed of the light
C:the number of particles in the air
D:the changes of the particles'speed答案：D解析：根据第二段第三句，再结合上文可知，clear-air turbulence指的是第二段第三段中的“unexpectedrough air"，又由于disturbed与rough意义相近，故选B。
根据二段最后一句可知，1997年12月份的晴空湍流导致1人死亡、100人受伤，可以说是造成了很多伤亡。
根据第四段最后一句可知，晴空湍流的强度与微粒速度的变化有关。
根据第五段最后一句可知，激光雷达探测器能够探测到前方3千米到8千米之间的晴空湍流，并且预测的晴空湍流的强度和持续时间与真实情况相符。这说明激光雷达探测器能成功地预测晴空湍流。
根据最后一段第二句可知，研究人员正计划改善激光雷达探测器，准备使用更强的电脉冲来提升激光雷达探测器的探测范围。 -
第20题：
Which one of the following ions would give a basic solution upon addition to water？（）
- A、NH4+
- B、Na+
- C、C2H3O2-
- D、NO3-
正确答案:C -
第21题：
单选题If over a period of weeks the air-box pressure of a turbo-charged, diesel engine, operating at full load, appears to be dropping off, the cause can be （）.Aopen air-box drains
Bloss of cooling water to the diffuser
Cgradual fouling of the air filters
Dimproperly timed exhaust valves
正确答案： A解析： 暂无解析 -
第22题：
单选题The statement that “the people own the air” implies that _____.Acitizens have the right to insist on worthwhile television programs
Btelevision should be socialized to cater to the nation’s whims
Cthe government may build above present structures
Dthe people own nothing, for air is worthless
正确答案： A解析：
第三段结尾部分，作者提到“the people own the air”，随后指出“无论是在夜晚的精华时段还是清晨，人们都拥有the air，因此广播公司每一时刻由于占用the air，都owe people something”，最后，作者指出广播公司偿还的方式是搞好服务，由此可判断，作者强调人们拥有天空，是暗示人们有权要求有意义的电视节目的播放，选项A正确。 -
第23题：
单选题At ground level, nitrous oxides are bad enough, but when up high, atmospherically they bond with free ions to create dangerous smog particles.Abut when up high, atmospherically they
Bhowever, it is in the upper atmosphere in which it may
Cbut in the upper atmosphere, they
Dhowever, but once in the upper atmosphere it is known to
Eas in the upper atmosphere they
正确答案： B解析：
主语为“nitrous oxides”为复数，故B、D错误。C项的表达比A项流畅，故本题选C项。