16.It ____ long before we ____ the result of the experiment.

问题描述:

16.It ____ long before we ____ the result of the experiment.
It ____ long before we ____ the result of the experiment.
A.will not be,will know B.is ,will know C.will not be ,know D.is ,know
,主将从现,那这是什么从句啊?

时间状语从句
not.before.跟not .until 类似.