when引导什么从句主将从现

　　例句：

　　When you think you know nothing, then you begin to know something.

　　当你以为自己一无所知的时候，你就是在开始知道一些事物了。

　　We were about to leave when he came in.

　　我们就要离开，就在那时他进来了。

　　When I lived in the countryside, I used to carry some water for him.

　　当我住在农村时，我常常为他担水。

　　When truth is buried under the ground ，it grows, it chokes, it gathers such an explosive force that on the day it bursts out , it blows up everything with it.当真理被埋在地下的时候，它在生长，它感到压抑，它蓄存着这么一种爆炸性力量，一旦冒出，它就会炸破一切。