I told him it was a bad idea,but Dave’s so __________ that he just never listens.

A．ambitious

B．roundabout

C．stubborn

D．straightforward

醇类消毒剂消毒诊疗器具，应将待消毒的物品浸没于装有70%～80%（体积比）的乙醇溶液中并加盖；消毒作用时间（），或进行表面擦拭消毒。

A.≥30min

B.≥20min

C.≥15min

D.≥10min

E.≥1h