— The terrible accident is under investigation．—

— The terrible accident is under investigation．— Actually, quicker action _____ those workers trapped in the mine．A.might have savedB.must have savedC.should have savedD.could have saved

D解析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。

谢谢了