---- Have you heard of Steven Jobs, the co-founder and CEO of Apple?

---- Yes, but it’s a pity that he has _____ for a half year..

A．died

B．been dying

C．been dead

D．death

Ⅱ相阻滞的特点有（）

A.四个成串刺激可出现衰减

B.肌松时间延长

C.无强直刺激后易化

D.不为抗胆碱酯酶药拮抗

E.给去极化肌松药后，一旦TOF比值≤50%时即可诊断