临床上，麻醉性镇痛药导致呼吸抑制时，采用的最佳拮抗剂是（）

A.吗啡

B.烯丙吗啡

C.纳洛酮

D.美沙酮

E.可待因

______ surprised the hostess most is _______ one of her friends left the party without saying a word.

A．What, what

B．What, that

C．That, that

D．That, what