单项选择题

The primary purpose of the passage is to ______.

A．discuss the significance of increasing the amount of carbon dioxide in the atmosphere
B．warn of the dangers of continued burning of fossil fuels
C．explain how a constant temperature is maintained in the Earth's surface
D．demonstrate the usefulness of mathematical models in predicting long-range climatic change
<上一题 目录 下一题>
热门 试题

单项选择题
According to the passage, which of the following is TRUE of the last hundred years
A．Fossil fuels were burned for the first time.
B．The average temperature at the Earth's surface has become 2℃ cooler.
C．The amount of carbon dioxide in the atmosphere has increased measurably.
D．The amount of farmland worldwide has double
单项选择题
According to the passage, the greatest part of the solar energy that reaches the Earth is ______.
A．reflected back to space by snow and ice
B．concentrated at visible wavelengths
C．absorbed by carbon dioxide molecules
D．absorbed by atmospheric water vapor
相关试题