-Mr. Smith must know a lot about Chinese history.---. He has studied it for years.A. So

问题补充：

---Mr. Smith must know a lot about Chinese history.

---. He has studied it for years.

A. So he does

B. So does he

C. So he must

D. Yes, he must

答案：

(答案→)A. So he does

B. So does he

C. So he must

D. Yes, he must

解析：

So somebody do的意思是“的却如此”，一般表示赞同某人某事；而So do somebody的意思是“谁谁谁也是这样的”，一般表示和某人、某事的情况一样；So he must 的意思是“因此他必须怎样怎样”，一般表示某人不得已必须要干某事；Yes，he must的意思是“是的，他必须这么做”，一般用再赞同某人的看法上。