Question

---She looks very happy.She_______have passed the exam.
---I guess so.It’s not difficult after all

1. A.
   should
2. B.
   could
3. C.
   must
4. D.
   might

Answer 1

C
“must have+動詞-ed形式”表示“一定做了某事”,根據(jù)所提供的情景“She looks very happy.”可判斷出她一定通過了考試。“should have+動詞-ed形式”表示“本來應(yīng)該做某事,而沒有做”,常用于表示責(zé)備。“could have+動詞-ed形式”在肯定句型中,往往用作委婉地批評，表示本應(yīng)該做什么,而沒做，有時(shí)也用作猜測�！癿ight have+動詞-ed形式”表示推測過去做過某事，“也許”發(fā)生了。