【题目】By the time the teacher _______ back, we ________ the thorough cleaning.
A. came, have finished B. comes, have finished
C. will come, will have come D. comes, will have finished
在线课程【答案】D
【解析】句意：到老师回来为止，我们将会完成彻底的打扫工作。根据句意可知，老师回来是将来，在时间状语从句中，从句用现在表示将来，主句用将来，此句根据语境要用将来完成时，故选D。