1、到...為止,一般要求主句用過(guò)去完成時(shí)。
He had left by the time we reached home.
當(dāng)我們到家的時(shí)候他已經(jīng)走了。
The movie had begun by the time we got there.
當(dāng)我們到那兒的時(shí)候,電影已經(jīng)開(kāi)始了。
2、…當(dāng)……的時(shí)候;
如果只是說(shuō)過(guò)去某個(gè)時(shí)候的狀況,用過(guò)去時(shí),而不用完成時(shí)。
By the time the war was over ,death and suffering were to be seen everywhere.
在戰(zhàn)爭(zhēng)結(jié)束的時(shí)候,到處可見(jiàn)死亡和饑餓.這里沒(méi)有“死亡和饑餓”已經(jīng)完成的意思,只是描述當(dāng)時(shí)這個(gè)時(shí)間點(diǎn)的狀況.所以用過(guò)去時(shí)。
By the time we arrived the meeting was over.
我們到達(dá)時(shí),會(huì)議已結(jié)束了。