问题补充:
I’m sorry you’ve been waiting for so long, but it’ll still be some time Brian gets back.
A. since
B. after
C. when
D. before
答案:
A. since
B. after
C. when
(答案→)D. before
解析:A. since自从B. after在…之后 C. when当...时候 D. before在…之前;句意:我很抱歉你等了这么长时间,但是在布莱恩先生回来之前还要一段时间。本题中it作为形式主语,before所引导的时间状语从句作为真正的主语,故选D