单选题Much of the night sky has never been examined carefully because of the cumbersome nature of telescopes and the fact that they can only peer into a tiny patch of the sky at one time.A of the cumbersome nature of telescopes and the fact that they can onl

Although a natural alternative,such as honey,can be used to sweeten food if this is necessary,we can in fact do without it.Nowadays fibre is considered to be an important part of a healthy diet.In white bread,for example,the fibre has been removed.But it is（ ）in unrefined flour and of course in vegetables.

A.current
B.substantial
C.present
D.essential

共用题干
Rockets in the Sky
If someone asked you,"What color is the sky?"I expect that you would answer,"Blue."I am afraid that you would be wrong.The sky has no color.When we see blue,we are looking at blue sunlight.The sunlight is shining on little bits of dust in the air.
We know that there is air all around the world.We could not breathe without air.Airplanes could not fly without air.They need air to lift their wings.Airplanes cannot fly very high because as they go higher the air gets thinner.If we go far enough away from the earth,we find there is no air.
What is the sky?The sky is space.In this space there is nothing except the sun,the moon and all the stars. Scientists have always wanted to know more about the other worlds in the space.They have looked at them through telescopes and in this way they have found out a great deal.The moon is about 384 ,000 kilometers away from the earth.An airplane cann't fly to the moon but there is a thing that can fly even when there is no air. This is rocket.
I am sure that you are asking,"How does a rocket fly?"If you want to know,get a balloon and then blow it up until it is quite big.Do not tie up the neck of the balloon.Let go!The balloon will fly off through the air very quickly.The air inside the balloon tries to get out.It rushes out through the neck of the balloon and this pushes the balloon through the air.It does not need wings like an airplane.
This is how a rocket works.It is not made of rubber（橡胶）like a balloon,of course.It is made of metal. The metal must not be heavy but it must be very strong.There is gas inside the rocket which is made very hot. When it rushes out of the end of the rocket,the rocket is pushed up into the air.
Rockets can fly far out into space.Rockets with men inside them have already reached the moon.Several rockets,without men inside them,have been sent to other worlds much farther away.One day rockets may be able to go anywhere in the space.

What color is the sky?
A:It is blue.
B:It is white.
C:It is grey.
D:It has no color.

It may be pointed out that warfare（战争）as practiced by man has no parallel in nature,This is to say that within the more highly developed animal populations of this earth,there is not now.nor has there been similar destruction within a species（物种）itself.In fact,one has to go to the lowliest forms of animal life,such as certain kinds of ants,to find anything comparable to human warfare.It is a curious fact that mankind appears to give the killing of his own kind a good reason by imaging that it is a"law of nature".There are now a lot of wrong ideas about the laws of nature,of which this is one of the most incorrect and fateful（致命的）.Political beliefs have been based upon it with results that have come near to destroying human civilization.The theory that war is a biological necessity.that it is nature′s method of controlling population and believing in the survival（生存）of the strong and the elimination（灭亡）of the weak,is totally wrong and insupportable.Within the last century.when wars have been common all over the world,the human population of the earth has almost doubled.

The author of this passage seems to be the"law of nature".

A.against
B.in favor of
C.uncertain of
D.very much interested in

It may be pointed out that warfare（战争）as practiced by man has no parallel in nature,This is to say that within the more highly developed animal populations of this earth,there is not now.nor has there been similar destruction within a species（物种）itself.In fact,one has to go to the lowliest forms of animal life,such as certain kinds of ants,to find anything comparable to human warfare.It is a curious fact that mankind appears to give the killing of his own kind a good reason by imaging that it is a"law of nature".There are now a lot of wrong ideas about the laws of nature,of which this is one of the most incorrect and fateful（致命的）.Political beliefs have been based upon it with results that have come near to destroying human civilization.The theory that war is a biological necessity.that it is nature′s method of controlling population and believing in the survival（生存）of the strong and the elimination（灭亡）of the weak,is totally wrong and insupportable.Within the last century.when wars have been common all over the world,the human population of the earth has almost doubled.

According to Sentence 2,which of the following is true?

A.The destruction is similar to the killing of each other within human beings.
B.There is not the similar destruction now,but it occurred before.,'
C.There is never a time when we may see the similar destruction.
D.The destruction is now a thing of the past.

Attention has already been drawn to the fact _________a single harmonization proposal can take decades to come to fruition.

A. that
B. as
C. which
D. where

根据以下材料，回答题
In a telephone survey of more than 2,000adults,21% said they believed the sun revolved (旋转) around the earth. An 51 7% did not know which revolvedaround 52. I have no doubt that 53 all of these people were 54 inschool that the earth revolves around the sun: 55 may even have written it 56 a test. But they never 57 their incorrect mental models ofplanetary(行星的) 58 because their everydayobservations didn′t support 59 their teachers told them: People seethe sun "moving" 60 the sky as morning turns to night, and theearth seems stationary(静止的) 61 that ishappening.
Students can learn the right answers 62 heart in class, and yet never combinedthem 63 their working models of the world.The objectively correct answer the professor accepts and the 64 personal understanding of the world can 65 side by side, each unaffected bythe other.
Outside of class, the students like to seethe 66 model because it has always worked well 67 that circumstance. Unless professorsaddress 68 errors in students′ personal models of the world, studentsare not 69 to replace them with 70 one.

根据以下材料，回答题
In a telephone survey of more than 2,000adults,21% said they believed the sun revolved (旋转) around the earth. An 51 7% did not know which revolvedaround 52. I have no doubt that 53 all of these people were 54 inschool that the earth revolves around the sun: 55 may even have written it 56 a test. But they never 57 their incorrect mental models ofplanetary(行星的) 58 because their everydayobservations didn′t support 59 their teachers told them: People seethe sun "moving" 60 the sky as morning turns to night, and theearth seems stationary(静止的) 61 that ishappening.
Students can learn the right answers 62 heart in class, and yet never combinedthem 63 their working models of the world.The objectively correct answer the professor accepts and the 64 personal understanding of the world can 65 side by side, each unaffected bythe other.
Outside of class, the students like to seethe 66 model because it has always worked well 67 that circumstance. Unless professorsaddress 68 errors in students′ personal models of the world, studentsare not 69 to replace them with 70 one.

It may be pointed out that warfare（战争）as practiced by man has no parallel in nature,This is to say that within the more highly developed animal populations of this earth,there is not now.nor has there been similar destruction within a species（物种）itself.In fact,one has to go to the lowliest forms of animal life,such as certain kinds of ants,to find anything comparable to human warfare.It is a curious fact that mankind appears to give the killing of his own kind a good reason by imaging that it is a"law of nature".There are now a lot of wrong ideas about the laws of nature,of which this is one of the most incorrect and fateful（致命的）.Political beliefs have been based upon it with results that have come near to destroying human civilization.The theory that war is a biological necessity.that it is nature′s method of controlling population and believing in the survival（生存）of the strong and the elimination（灭亡）of the weak,is totally wrong and insupportable.Within the last century.when wars have been common all over the world,the human population of the earth has almost doubled.

What does the"law of nature"mean?You can find the answer in the passage in

A.the first sentence
B.the fourth sentence
C.the seventh sentence
D.the final sentence

It may be pointed out that warfare（战争）as practiced by man has no parallel in nature,This is to say that within the more highly developed animal populations of this earth,there is not now.nor has there been similar destruction within a species（物种）itself.In fact,one has to go to the lowliest forms of animal life,such as certain kinds of ants,to find anything comparable to human warfare.It is a curious fact that mankind appears to give the killing of his own kind a good reason by imaging that it is a"law of nature".There are now a lot of wrong ideas about the laws of nature,of which this is one of the most incorrect and fateful（致命的）.Political beliefs have been based upon it with results that have come near to destroying human civilization.The theory that war is a biological necessity.that it is nature′s method of controlling population and believing in the survival（生存）of the strong and the elimination（灭亡）of the weak,is totally wrong and insupportable.Within the last century.when wars have been common all over the world,the human population of the earth has almost doubled.

The main idea of this passage is

A.warfare is a"law of nature"
B.warfare is not a"law of nature"
C.warfare does not control human population
D.none of the lowlier animals,except ants,practice warfare upon their own species