You will have to wait for one more week, _____ the manager will be back from his trip.

You will have to wait for one more week, _____ the manager will be back from his trip.

A.after

B.while

C.when

D.since

答案及解析： C

when引导的非限定性定语从句，本句中的when =" by" which time，“到那时候”。after和since都错在时间的先后顺序，而while引导时间状语从句不用将来时。