I’m sorry you’ve been waiting so long but it is still some time Brian gets back.A. befor

问题补充：

I’m sorry you’ve been waiting so long, but it is still some time Brian gets back.

A. before

B. since

C. till

D. after

答案：

(答案→)A. before

B. since

C. till

D. after

解析：考察固定句型。It be 一段时间 before从句，指一段时间以后某事才发生。句意：对不起让你久等了，但还要有一段时间以后Brian才你能回来。故A正确。