(1) before sb can/ could … 某人还没来得及……

例：Before I could get in a word ，he had measured me.

我还没来得及插话，他就给我量好了尺寸。

(2) It will be 时间 before 从句； 还有多长时间……

例：It will be 4 years before he graduates.

他还有四年时间变毕业了。

(3) had done some time before (才……)

例：We had sailed four days and four nights before we saw land.

我们航行了四天四夜才见到陆地。

(4) had not done ... before ... 不到……就……

例：We hadn’t run a mile before he felt tired.

我们还没走到一英里路就觉得累了。

(5) It was not 一段时间 before 不多久就……

例：It wasn’t two years before he left the country.

还没到两年他们离开了那国家。