－Last month Shirley advised her father to buy her brother ________MP4 as a birthday present.

－_______ useful advice it was!

A．a; How

B．an; What a

C．an; What

D．/; How an

拆除工程施工现场应按规定设置不低于（）m的硬质围挡，并在施工危险部位设置醒目的警示标志。

A、1.5

B、1.8

C、1.6