___ most of the earth’s surface is covered by water, fresh water is very rare an

题型：不详难度：来源：

___ most of the earth’s surface is covered by water, fresh water is very rare and precious.

A．As

B．Although

C．If

D．Once

答案

B

解析

试题分析：句意：尽管地球的表面覆盖着水，但是淡水还是稀少的和宝贵的。as因为；         although尽管； if 如果； once一旦。根据句意故选B。
点评：本题难度适中。判断从句中用哪个连词，需用记住连词的用法，在句中的作用，连词也是高考的热点，需要考生平时多练习。需要考生会分析句子成分理解句意。
即学即练：___ these terms are not acceptable to you, we may suggest others.
A. As         B. Although    C. If         D. Once
解析：C。句意：如果你对这些条件不合意，我们可提出别的条件。