—Not unless he ______ his homework.

A. has finished B. finished

C. is to finish D. would finish

【答案】A

【解析】考查动词的时态。在unless引导的条件状语从句中，用现在完成时代替将来完成时。句意：——汤姆可以去踢足球吗？——除非他完成作业，否则不能出去。