--- ________ the class done most of the work?

--- Yes, but the rest ___________ rather difficult.

A．Has, are

B．Has, is

C．Have, are

D．Have, is

休克时应用血管活性药物（）。

A.提高血压是应用的首要目标

B.不会加重肾缺血

C.不增加心脏收缩力

D.提高组织的血液灌流量

E.降低组织代谢