题目内容
Many gases in the atmosphere actually heat energy that escapes from the Earth’s surface back to the earth.
A. finding; reflecting B. found; reflected
C. found; to reflect D. found; reflect
D
【解析】略
We experience different forms of the Sun’s energy every day. We can see its light and feel its warmth. The Sun is the major source of evaporation (蒸发) of water from the oceans and lakes. Sunlight also provides the energy used by green plants to make their own food. These green plants then provide food for all organisms (生物) on the Earth.
Much of the energy that comes from the Sun never reaches the Earth’s surface. It is either reflected or absorbed by the gases in the upper atmosphere. Of the energy that reaches the lower atmosphere, 30% is reflected by clouds or the Earth’s surface. The remaining 70% warms the surface of the planet, causes water to evaporate, and provides energy for the water cycle and weather. Only a tiny part, approximately 0.023%, is actually used by green plants to produce food.
Many gases found in the atmosphere actually reflect heat energy escaping from the Earth’s surface back to the Earth. These gases act like the glass of a greenhouse in that they allow energy from the Sun to enter but prevent energy from leaving. They are therefore called greenhouse gases.
When sunlight strikes an object, some of the energy is absorbed and some is reflected. The amount reflected depends on the surface. For example, you’ve probably noticed how bright snow is when sunlight falls on it. Snow reflects most of the energy from the Sun, so it contributes to the low temperatures of winter. Dark-coloured surfaces, such as dark soil or forest, absorb more energy and help warm the surrounding air.
【小题1】According to the passage, the root cause for weather changes on the Earth is ______.
| A．the atmosphere surrounding the Earth | B．water from oceans and lakes |
| C．energy from the Sun | D．greenhouse gases in the sky |
| A．absorbed by the clouds in the lower atmosphere |
| B．reflected by the gases in the upper atmosphere |
| C．lost in the upper and lower atmosphere |
| D．used to evaporate water from the oceans and lakes |
| A．all living things on the Earth depend on the Sun for their food |
| B．a forest looks dark in winter because it absorbs solar energy |
| C．only 0.023% of the energy from the Sun is made use of on the Earth |
| D．greenhouse gases allow heat energy to escape from the Earth’s surface |
The earth is the only planet that scientists are certain has life .What does the earth have that the other planets don’t ? For one thing , the earth has just the right temperature . As the third planet from the sun , the earth seems to be just the right distance away . The planets that are closer to the sun are so hot that their surfaces bake in the sun . The farthest planets are cold balls .
When the earth developed— which scientists believe may have happened about billions of years ago , many gases covered the earth . The gases caused the earth to be hot . But something wonderful happened . The temperature was just right for thick clouds to form . It rained very hard for a very long time . This gave the earth its oceans . Water made it possible for plants to grow . The plants created oxygen in the atmosphere . Oxygen is the gas that humans and animals breathe .
Only one other planet in the solar system seems to be something like the earth . That planet is Mars . Mars is smaller than the earth , and it is quite a bit cooler . But it is not too cold for humans . On some days , the temperatures are as cold as a winter day in the northern United States . If you wore a special spacesuit , you could walk around on Mars . You would have to bring your own air to breathe , though . The air on Mars is too thin to breathe . Mars has the largest volcano in the solar system . It is sixteen miles high . The highest volcano on the earth is five miles high . The most unexpected sight on Mars is dried-up river beds . Scientists believe that Mars was once much wetter that it is now . Does this mean there could have been living things on Mars ? Scientists are not sure , but there has been no sign so far .
【小题1】It is the on the earth that makes life possible .
| A．temperature | B．water | C．oxygen | D．temperature , water and oxygen |
| A．the sun | B．the earth | C．the moon | D．Mars |
| A．Mars . | B．Moon . | C．Sun . | D．Mars and Moon . |
| A．The earth has a history of about 4 million years . |
| B．There is no air on Mars . |
| C．The largest volcano on Mars is over three times higher than the highest one on the earth |
| D．Scientists believe there are living things on Mars . |
| A．Living Things on Our Earth | B．The Moon |
| C．Living Things on the Moon | D．Mars Is Most Like the Earth |