— The terrible accident is under investigation.

— Actually, quicker action _________ those workers trapped in the mine.

A．may have saved

B．must have saved

C．should have saved

D．could have saved

可以认为，咽门为食道，属咽，颃颡与喉咙为气道，属喉，喉关既为食道而属咽，亦为气道也属喉，故喉关既属咽，也属喉。