18．—Jim, are you ______ this Saturday?

—Oh, sorry. I need to go to the bookshop _____ the bank on Saturday.

A．convenient; and

B．convenient; as well as

C．available; as well as

D．available; with

中心静脉压低，血压低提示（）。

A.心功能不全，血容量正常

B.血容量不足

C.容量血管过度收缩

D.心功能不全或血容量相对过多

E.心功能不全或血容量不足