all living things on the earth depend on the sun for their food
a forest looks dark in winter because it absorbs solar energy
only 0.023 of the energy from the sun is made use of on the earth
greenhouse gases allow heat energy to escape from the earth’ s surface
第1题：
We can use energy from the sun because ______.
第2题：
24． The passage tells us __________．
A． the sun is not the biggest star
B． the sun is bigger than any other star
C． only the sun can shine
D． the sun is one of the farthest stars from us
第3题：
A.derive
B.to derive
C.deriving
D.of deriving.
第4题：
To get some idea of the amount of heat the sun ________(1), think about this. If you ________(2)collect all the heat that hits the earth in a two-week period, it would equal the amount of all the other known sources and reserves of energy: wood, coal, and oil. But even these sources of energy depend ________(3) the sun for their formation. For example, a tree ________ (4) certainly never grow and provide fuel in the form. of wood were it not for the sun. Because the sun is so important in the production of all forms of heating fuel, more and more time and money are being spent ________(5) ways to change power from the sun directly into a form. of heat.
1.
A、gives off
B、turns off
C、takes off
D、sets off
2.
A、will
B、could
C、must
D、shall
3.
A、of
B、in
C、on
D、to
4.
A、will
B、must
C、shall
D、would
5.
A、study
B、studied
C、studying
D、being studying
第5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.
第6题：
A
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
第7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．
第8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 ______
第9题：
A greenhouse is a building made of glass which is used for keeping plants when the outside temperature is low. In a similar way there are several gases in the atmosphere which trap(捕捉)the heat produced by the sun and prevent it from escaping. These gases are known as"greenhouse gases"，and the way in which they trap heat in the atmosphere is called the "greenhouse effect". This is not simply air pollution. Most of the main greenhouse gases exist naturally in small amounts in our atmosphere, and without them earth would be 30 degrees colder and human life would not exist. In other words, the greenhouse effect is a natural course which is to some degree helpful to us.
The problem is that in the last century and a half, we have been putting too many of these gases into the earth's atmosphere by burning large quantities of coal and oil and by cutting down forests. The rapid increase in greenhouse gases is making the world warmer. The world's temperature has already gone up by half a degree this century, and the sea level has risen by 10 centimetres. If the amount of carbon dioxide(二氧化碳)in the atmosphere doubles, there will probably be a rise in the earth's temperature of between 1 and 4 degrees. This may seem a small increase, but it would be enough to cause major changes in geography and agriculture. Large areas of the world would be flooded, and some areas would become dry and unable to produce crops. It is important, too, to consider that there may be a delay of about 30 years in the greenhouse effect. This means that we are probably experiencing only now the effect of the gases put into the atmosphere before the 1960s. Since then, our use of these gases has greatly increased.
1. The"greenhouse effect"means _____.
A. the way in which gases are used for keeping plants warm
B. a natural course which is some degree helpful to us
C. the way"greenhouse gases"trap heat on the earth
D. the whole course in which greenhouse gases prevent heat
2. If there were no greenhouse effect, _____.
A. no plants would grow on our planet
B. earth would be thirty degrees colder
C. man could not live on the earth
D. All of the above answers are correct
3. Which of the following is NOT true? _____
A. Burning too much coal and oil produces lots of greenhouse gases.
B. It has become warmer on the earth now than in the past.
C. Gases put into the atmosphere now will affect the earth years later.
D. The temperature in a greenhouse is as high as that in the atmosphere.
4. Suppose the earth's temperature rose by 3 degrees, _____.
A. great harm would be done to mankind
B. the sea level would go by 10 centimetres
C. all the land in the world would be flooded
D. crops would be unable to grow on the earth
5. This passage mainly deals with _____.
A. the concept(概念)and harm of greenhouse effect
B. the relation between greenhouse gases and man
C. the concept and change of greenhouse effect
D. the effect of the rise of the earth's temperature
第10题：
Neap tides occur ______.
A.at the start of spring, when the Sun is nearly over the equator
B.only when the Sun and Moon are on the same sides of the Earth and are nearly in line
C.when the Sun and Moon are at approximately 90°to each other, as seen from the Earth
D.when the Sun , Moon, and Earth are nearly in line, regardless of alignment order