My colleague has been recovering gradually since the operation and it wont’ be long he

问题补充：

My colleague has been recovering gradually since the operation, and it wont’ be long he comes back to work．

A. before

B. since

C. after

D. when

答案：

(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