单项选择题

How much of the world's land surface is at risk of becoming desert

A．Less than ten million square kilometers.
B．Twenty million square kilometers.
C．Mom than twenty million square kilometers.
D．30% of the world's land surfac

<上一题目录下一题>

热门试题

单项选择题

Desert soils break up and crack because of ______.

A．the effects of wind and rain.
B．the lack of protection from the sun.
C．the tropical location of deserts.
D．the absence of min.

单项选择题

What does the writer think about the creation of new desert areas

A．It is a natural development.
B．The problem is not very serious.
C．It is a very worrying problem.
D．The situation will improve in tim