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

来源:百度知道 编辑:UC知道 时间:2024/06/10 08:55:37
__ most of the earth's surface is covered by water,fresh water is very rare and precious.
A.as B.once C.if D.although
答案是 A
为什么?
请详细说明,分析每个选项,谢谢~

应该是选D吧``
虽然地球上表面大部分都被水覆盖,但淡水还是非常稀有和珍贵

~A选项,as 表由于的意思,是作连词连接句子的。即由于most of the earth's surface is covered by water,所以fresh water is very rare and precious. 很合理,选A。
~B选项,虽说once也可以作连词连接句子,但是表一旦的意思,根本不符合地球的实际情况(意思是说,地球还未被海洋覆盖大部分表面),不选。
~C选项,if表如果,也不符合地球的实际情况,跟上面犯了一样的逻辑错误。
~D选项,although表虽然,你试试,这样的话存在语病。