My colleague has been recovering gradually since the operation, and it wont’ be long he es back to work．
A. before
B. since
C. after
D. when
网友回答
(答案→)A. before
B. since
C. after
D. when
解析：考查连词，before 意思“（直到…）才”，since意思“自从”，after意思“…之后”， when意思“当……时候”，句子意思“自从做完手术，我的同事一直在恢复，直到他回去工作用不了多长时间”，所以选A