Question

16．众所周知，大量砍树对自然平衡有灾难性的影响．（As）As we all know/As is known to all，cutting down a large number of trees has disastrous effects on the balance of nature．．

Answer 1

分析 As we all know/As is known to all，cutting down a large number of trees has disastrous effects on the balance of nature．

解答 As we all know/As is known to all，cutting down a large number of trees has disastrous effects on the balance of nature．
这里是介绍的一个基本道理，所以用一般现在时．根据句意"众所周知"可知运用as引导的非限制性定语从句，后面的主句用动名词短语作主语．
As we all know/As is known to all 众所周知；cut down 砍伐、砍到，the balance of nature 自然平衡．

点评 对于as引导的非限制性定语从句要掌握一些基本的表达方式；如：
as is often the case（这是常有的事），as was expected（不出所料），as often happens（正如经常发生的那样），as is known to all（众所周知），as has been said before（如上所述），as is mentioned above（正如上面所提到的）等．