---The woman biologist stayed in Africa studying wild animals for 13 years befor

---The woman biologist stayed in Africa studying wild animals for 13 years before she returned．

---Oh, dear! She ______ a lot of difficulties!

A.may go through

B.might go through

C.ought to have gone through

D.must have gone through

试题答案

D

前者所说句意为“这位女生物学家回来之前，在非洲住了13年研究野生动物”。因此后者所说“她一定渡过了很多难关”。这一过程应该是过去的事情，用情态动词对过去情况进行推测，应该用“情态动词+have done”这一结构，故排除A和B项；ought to have done相当于should have done，意为“本应该做某事但事实上没有做”，不符合题意，故排除C项；must have done意为“一定已经做了……”，符合题意。