问题补充：
Ever since the financial crisis , many workers from their jobs.
A. broke out; were laid off
B. has broken out; were laid off
C. had broken out; had been laid off
D. broke out; have been laid off
答案：
A. broke out; were laid off
B. has broken out; were laid off
C. had broken out; had been laid off
(答案→)D. broke out; have been laid off
解析：
这题考查时态的用法,因为是since引导的时间状语从句，所以第一空填过去时，主句用现在完成时。句意是：自从经济危机爆发，很多工人被解雇了。选D。
