30分析此句:As is mentioned above,the number of the students in senior high school is increasing.

问题描述:

30分析此句:As is mentioned above,the number of the students in senior high school is increasing.

the number of the students in senior high school is increasing是主句.
As is mentioned above是个定语从句,
as是关系代词,在从句中作主语,代替整个主句the number of the students in senior high school is increasing.
全句意思是:
正如上面所提到的一样,高中生的数量在增加.