The energy which the sun radiates goes
in every direction, and only a minute part of it falls on the earth. It is
reported that some scientists believe less than 1% of the solar energy fallen on
the earth has been used so far. Even so, it represents power of approximately 5,
000,000 horsepower per square mile per day; the sun gives us as much energy
every minute as mankind utilizes in a year. At present, because of the lack of
scientific knowledge, we use this energy indirectly, and it is our only final
source of power. Coal represents the chemical action of the sun on green plants
thousands of years ago. Waterpower results from the sun's creating vapor and
subsequent rain. Even windmills operate because of air currents set in motion by
the different heating effects of the use this immense source of energy more
directly. Already, scientists have worked out a new type of energy, surprisingly
efficient, in which the sun's rays are concentrated through mirrors on a tube of
water to create steam.
单选题
The word "minute" in the first sentence most probably means ______.
单选题
The extent to which mankind utilizes solar energy available is approximately ______.
【正确答案】
A
【答案解析】细节题。从文章第二句话“It is reported that some scientists believe less than 1% of the solar energy fallen on the earth has been used so far．”可知：目前为止，人们只用了太阳能的1%。因此不难得出答案A。
单选题
Man cannot directly utilize the solar energy falling on the earth because ______.
【正确答案】
D
【答案解析】细节题。从文章第四句话“At present，because of the lack of scientific knowledge，we use this energy indirectly，and it is our only final source of power．”可知：由于人类缺少相关的科学知识，太阳能现在只是间接地在使用。因此，D选项为最佳答案。