All the useful energy at the surface of the earth comes from the activity of the sun. The sun heats and feeds creatures and mank

admin2018-02-03  52

问题     All the useful energy at the surface of the earth comes from the activity of the sun. The sun heats and feeds creatures and mankind. Each year it provides men with two hundred million tons of grain and nearly ten million tons of wood, coal, oil, natural gas, and all other fuels are stored energy from the sun. Some was collected by this season’s plants as carbon compounds. Some was stored by plants and trees ages ago. Even waterpower derives from the sun. Water turned into vapor by the sun fails as rain. It courses down the mountains and is converted to electric power. Light transmits only the energy that comes from the sun’s outer layer, and much of this energy that is directed towards the earth never arrives. About nine tenths of it is absorbed by the atmosphere of the earth. In fact, the earth itself gets only one half millionth of the sun’s entire output of radiant energy.  
Of the sun’s total output of radiant energy, the earth receives

选项 A、one tenth
B、one millionth
C、all that comes from the surface of the sun
D、a very small portion

答案D

解析 事实细节题。文中最后一句说,事实上,地球只接收了太阳所有辐射能量的百万分之零点五,所以是相当小的一个比例。
转载请注明原文地址:https://kaotiyun.com/show/bwCO777K
0

最新回复(0)