出血坏死性胰腺炎最常见的并发症是（）
A.化脓性腹膜炎
B.败血症
C.消化道出血
D.胰周围脓肿
E.休克
参考答案：E
—Where _____ Mary have put the empty bottles?
— She _____ them away. They must be somewhere.
A．can; can’t have thrown
B．must; needn’t
C．must; must have thrown
D．can; mustn’t have thrown
利群卡的双重积分是什么？
