题目

- What did Mr. Smith do before he came to China?- He ______ in a car factory.A. works            B. worked           C. is working       D. will work 答案： 答案：B 解析:考查点：本题考查时态的用法。解题思路：根据题意：-在来中国之前Mr. Smiths是干什么工作的？-他在汽车厂上班。问句用中有“before he came to China”表示过去的时间状语，则回答应使用过去时态。故本题选B。已知Z=3+4i，则Z+1Z= ．