问题补充：
------Thank you very much for giving me a hand when I was in trouble.
------Don’t mention it. I only did what anyone else in my place.
A. must do
B. might do
C. would have done
D. can have done
答案：
A. must do
B. might do
(答案→)C. would have done
D. can have done
解析：考查情态动词用法。根据 for giving me a hand when I was in trouble可知，此处是对故去的虚拟，排除AB. Would have done意为我只是做了别人都会做的事情。 Can have done意为可能做了某事，不符合题意。
