It will be at least three weeks he recovers from his illness and returns to work.A. before

问题补充：

It will be at least three weeks he recovers from his illness and returns to work.

A. before

B. when

C. since

D. after

答案：

(答案→)A. before

B. when

C. since

D. after

解析：考查固定句型。It be 一段时间before从句，意为：一段时间以后某事才发生。句意：至少3个星期以后他才从疾病中恢复重新回到工作岗位上。