The teacher have thought Johnson was worth it or she wouldn’t have wasted time on him I

问题补充：

The teacher have thought Johnson was worth it or she wouldn’t have wasted time on him, I suppose.

A. should

B. can

C. would

D. must

答案：

A. should

B. can

C. would

(答案→)D. must

解析：“must+have+过去分词”表示对过去情况的肯定推测。句意为：我想，老师一定认为约翰逊是值得教的，要不然她就不会在他身上浪费时间了。