If you say that some people are selfless, you agree because they ______ other people more than themselves.

Why didn't you tell me earlier?

I tried to call you, but the line was busy; I can't ________ to you.

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—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

— 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

Perce Blackborow and his companions stayed on Elephant Island for six months before rescue came, so they ________ a lot of difficulties.

   A. must go through                          B. may go through

   C. must have gone through                    D. could have gone through