I'm sorry to have you waiting so long for Marcia,and I am af

I'm sorry to have you waiting so long for Marcia,and I am afraid it'll be ten minutes ____ she comes back.
A,before B.after C.until D.when
答：A.
译：对不起让你久等Marcia了,恐怕要过10分钟她才会回来.
析：有四个句型,很有用又很容易混淆：
before 之过去句型：It was some time before sth.happened.过了多久才发生某事.
before 之将来句型：it will be some time before sth.happens.要过多久才会发生某事.
since 句型：it is (=has been) some time since sth.happened.自某事发生以来,已经多少时间了.
when句型：it was 时间点（如1997） when sth.happned.某事发生时,时间是1997年.
that 强调句型：It was 时间状语（如in 1997) that sth.happened.为sth.happned in 1997.之强调时间状语.
本题为before的将来用法.

A

A