验算软弱下卧层强度时，软弱下卧层顶面的压力与承载力应符合下列（）组合。（）

A.

B.

C.

D.

--It is really fun to hike and I often go hiking in the forest.

--But hiking alone in the forest ______ be very dangerous.

A．can

B．must

C．shall

D．will