We can use energy from the sun because ______.

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第1题：

23．The moon is bright because__________

A． there is some fire 'on it

B． it is near the sun，too

C． there is big mirror on it

D． it can get light from the sun

正确答案：D
23.D【解析】由第三段最后一句“It gets its light from the sun”可知。

第2题：

For what purpose are the diving pipes used?

A. To absorb heat from the sun.

B. To store heat for future use.

C. To turn solar energy into heat energy.

D. To carry heat down below the surface.

正确答案：D

第3题：

Electromagnetic Energy

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.

The sun is 93 million miles from the earth. Yet we can use energy from the sun because electromagnetic energy travels through space.

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 mush 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.

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.

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).

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.

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. X-rays Are Used to Detect and Treat Cancer.

E. Seeking New Sources of Energy

F. Nuclear Energy is Beginning to Compete with Coal

Paragraph 3 ______

正确答案：C
C 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 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5题：

By no means ______ destroy or create energy.

A、we shall

B、shall we

C、can’t we

D、we can

参考答案：B

第6题：

25． Why do we call the sun"a life-giving star"?

A． Because it gives us warmth．

B． Because there are some living things on it．

C． Because plants and animals can't live without it．

D． Because people have to live in the dark without it．

正确答案：C
z5.C【解析】由最后一段中“The' sun gives us...1t makes life possible on our earth.”可知。

第7题：

We mustn’t judge a person from his appearance, because appearance can be ________.

A.influential

B.deceptive

C.complementary

D.prospective

答案：B

解析：influential意为“有很大影响力的，有支配力的”；deceptive意为“欺骗性的，骗人的”；complementary意为“互补的，补充的”；prospective意为“潜在的，期望的”。根据题干前半句句意“我们不能以貌取人”，可知后半句想表达的意思是“外貌具有欺骗性”。故本题选B。

第8题：

When you look at the sky at night，the moon looks bigger than the stars． In fact，the moon is much smaller than the stars．It is much smaller than the earth． But the moon is much closer to us than any star． That is why it looks so big． If you hold a coin close．to your eye，it looks big．If you look at it across the room，it looks small．The moon moves around the earth． It makes one trip in about four weeks． The moon looks flat(扁的)to us． But it is a round ball，like the earth．People once thought the moon had fire(火) on it． They thought the fire made it bright．Now we know the moon is like a mirror( 镜子 )． It gets its light from the sun Our sunlight comes from the sun，too: What is the sun? The sun is star． The stars we can see have their own light． There are many big stars we can-t see． Their light has burned out． Others are still bright，but they are so far away that we can-t see them． The sun looks bigger and much brighter than other stars because it is the nearest of all stars． The sun and the other stars we see are very hot，but the air around us saves us from(使------免于) the heat(热量) of the sun．The sun gives us light and warmth．It makes plants grow and leaves turn green． It makes life possible on our earth．It is a life-giving star．

( )21． The moon looks bigger because__________ ．

A． some stars are smaller than it

B．it is between the sun and the earth

C．it is the closest to the earth

D．it is very bright

正确答案：C
．21.C 【解析】由第一段中。But the moon is much closer to us than any star.打可知。

第9题：

Passage 1
Plants and animals that have been studied carefully seem to have built-in clocks. These biological clocks, as they are called, usually are not quite exact in measuring time. However, they work pretty well because they are "reset" each day, when the sun comes up.
Do pigeons use their biological clocks to help them find directions from the sun? We can keep pigeons in a room lit only by lamps. And we can program the lighting to produce artificial "days",different from the day outside. After a while we have shifted their clocks. Now we take them far away from home and let them go on a sunny day. Most of thegn start out as if they know just which way to go, but choose a wrong direction. They have picked a direction that would be correct for the position of the sun and the time of day according to their shifted clocks.
It is known and experimented that homing pigeons can tell directions by the sun. But what happens when the sky is darkly overcast by clouds and no one can see where the sun is? Then the pigeons still find their way home. The salne experiment has been repeated many times on sunny days and the result was always the same. But on very overcast days clock-shifted pigeons are just as good as normal pigeons in starting out in the right directions. So it seems that pigeons also have some extra sense of direction to use when they cannot see the sun.
Naturally, people have wondered whether pigeons might have a built-in compass—something that would tell them about the directions of the earth's magnetic field. One way to test that idea would be to see if a pigeon's sense of direction can be fooled by a magnet attached to its back.
With a strong magnet close by, a compass can no longer tell direction.
To test the idea, a group of ten pigeons had strong little magnet bars attached to their backs.
Another group carried brass bars instead which were not magnetic. In a number of experiments,both groups were taken away from home and let go. On sunny days none of the magnet-pigeons was fooled. They were just as good as the brass-pigeons in starting out in the right direction toward home. On cloudy, overcast days, however, with no sun the brass-pigeons chose the right direction,but the magnet-pigeons were in trouble. They later started out in different directions and acted completely lost.

Which is true about pigeons' finding directions?
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A．With a brass on back they can find directions sooner.
B．They can find directions better than other birds.
C．They use the earth's magnetic field and the sun to find directions.
D．They can find directions only to their home.

答案：C

解析：

根据文中研究太阳和地球磁场对鸽子生物钟影响的实验可知，二者都能帮助鸽子辨别方向。因此C项正确。

第10题：

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：

We can use energy from the sun because ______.

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