刚性基础在中心受压时，基底的沉降分布图形可简化为：（）

A.矩形

B.抛物线形

C.钟形

D.马鞍形

The jackknife stored on an inflatable liferaft will always be located（）.

A.in one of the equipment bags

B.in a special pocket near the forward entrance

C.on a cord hanging from the canopy

D.in a pocket on the first aid kit