(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 + 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。