John _____ have said such a thing about you. He never speaks ill of you behind your back. [ ]

A. needn't

B. might not

C. can't

D. mustn't

县级以上人民政府建立和完善突发事件( )

A．预防为主
B．预防为主、常备不懈
C．统一领导、分级负责
D．统一领导、统一指挥
E．调查、控制和医疗救治