— I am afraid I can't return the book to you before Friday. 

— _____. [ ]

A. Don't be afraid

B. Be careful

C. Not at all

D. Take your time

初产妇，27岁，17周妊娠，有风湿性心脏病，二尖瓣狭窄史，心功能Ⅱ级。

下列不必要的检查是（）。

A.血常规、尿常规

B.肝肾功能

C.胸片

D.B超

E.定期监测胎盘功能