识别是什么从句
问题描述：
识别是什么从句
Make sure that there are no mistakes in your papers before you turn them in
是主语从句吗?
答
这是一个含有宾语从句的祈使句.
主句：Make sure
宾语从句：that there are no mistakes in your papers before you turn them in.
在这个宾语从句中,又含有一个时间状语：before you turn them in.