Question

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

Answer 1

C

解析:

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。