The number of senior high school students is increasing...The number of senior high school students is increasing,as is mentioned above.请问这个句子后面的部分 as is mentioned above 为什么没有it?

来源:学生作业帮助网 编辑:作业帮 时间:2024/05/14 00:02:08

The number of senior high school students is increasing...
The number of senior high school students is increasing,as is mentioned above.
请问这个句子后面的部分 as is mentioned above 为什么没有it?

这里是as单独引导定语从句,先行词可以是一个词,也可以是一个句子或短语.例如:
(1) She is late, as is often the case.她迟到了,这是经常的事.(先行词是整个主句)
(2) To shut your eyes to facts, as many of you do, is foolish.对事实视而不见--你们好多人都是如此的愚蠢.(先行词是不定式短语)