Poorer families often lack ______ to a car, which they need to drive their children to a more successful school outside their own district.

A．approach

B．access

C．appeal

D．assessment

建筑石膏或粉刷石膏，一般采用袋装，自生产之日算起贮存期为（）。

A.三个月

B.四个月

C.五个月

D.半年