by the time的用法:
1、到…時候為止:
表示到...為止,一般要求主句用過去完成時.
例句:
He had left by the time we reached home.
當我們到家的時候他已經走了.
The movie had begun by the time we got there.
當我們到那兒的時候,電影已經開始了.
2、到……的時候:
(1)可以表示將來的.時間. 主句用將來完成時,而從句用一般現在時來表示將來的動作.
I will have finished the work by the time my father comes back.
(2)可以表示過去的時間. 主句用過去完成時,而從句用一般過去時.
He had built a lab for himself by the time he was 12 years old.
注:如果只是說過去某個時候的狀況,用過去時,而不用完成時。
例句: By the time the war was over , death and suffering were to be seen everywhere.
在戰爭結束的時候,到處可見死亡和飢餓。
這裡沒有“死亡和飢餓”已經完成的意思,只是描述當時這個時間點的狀況。所以用過去時。