A、Most of it is lost in the upper and lower atmosphere. B、Most of it is reflected by the gases in the upper atmosphere. C、Most o

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问题  
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 energy for our planet. It causes the evaporation 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 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-colored surfaces, such as dark soil or forest, absorb more energy and help warm the surrounding air.
Questions 29 to 31 are based on the passage you have just heard.
29. What is the root cause for weather changes on the Earth according to the passage?
30. Why does only a small part of the Sun’s energy reach the Earth’s surface?
31. What do we learn from the passage?

选项 A、Most of it is lost in the upper and lower atmosphere.
B、Most of it is reflected by the gases in the upper atmosphere.
C、Most of it is absorbed by the clouds in the lower atmosphere.
D、Most of it is used to evaporate water from the oceans and lakes.

答案A

解析 由选项中重复出现的Most of it is及lost,reflected,absorbed,used to evaporate及atmosphere等可推断,it指代energy from the sun,故本题很可能考查太阳射向地球的大部分能量受大气层的影响而无法到达地球表面的原因。短文中提到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,也就是说太阳的能量被上层大气反射或吸收,当剩下的能量穿过低大气层,有30%的能量被云或地球表面反射出去,最后只剩下一小部分到达地面,故答案为A)。
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