by the time的用法及例句
by the time意为“到……时候(为止)”,是一个介词短语,在句中经常起连词作用,引导时间状语从句。
by the time的用法
1、到…时候为止
表示到...为止,一般要求主句用过去完成时.
例句:
He had left by the time we reached home.
当我们到家的时候他已经走了.
The movie had begun by the time we got there.
当我们到那儿的时候,电影已经开始了.
2、到……的时候
(1)可以表示将来的时间. 主句用将来完成时,而从句用一般现在时来表示将来的动作.
I will have finished the work by the time my father comes back.
(2)可以表示过去的时间. 主句用过去完成时,而从句用一般过去时.
He had built a lab for himself by the time he was 12 years old.
注:如果只是说过去某个时候的状况,用过去时,而不用完成时。
例句: By the time the war was over , death and suffering were to be seen everywhere.
在战争结束的时候,到处可见死亡和饥饿。
这里没有“死亡和饥饿”已经完成的意思,只是描述当时这个时间点的状况。所以用过去时。