问题
选择题
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
答案
答案：C
考查情态动词。根据题意可知本句为对过去事情的推测，故用情态动词+ have done，根据句意可知must have done过去一定做某事，选C。