Children are not recommended to see such films         bad for their mental development.

A．that is

B．that are

C．as are

D．as is

机动船、人力船、排筏停？白时，白天应显示（）。

A.一个圆球

B.船首、尾各显示一个圆球

C.垂直两个圆球

D.垂直三个圆球