Question

— The terrible accident is under investigation．— Actually, quicker action _____ those workers trapped in the mine．

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

Answer 1

D
考查情态动词及虚拟语气。might have done 对过去可能性的推测，must have done对过去肯定的推测，should have done本应该做某事，实际上没有做，could have done本可以做某事，实际上没做，根据句意更快的行动本可以救那些困在矿中的工人的。所以选D。