—It was cold and the road was icy.

—It          a comfortable journey.

A．can’t be

B．shouldn’t be

C．mustn’t have been

D．couldn’t have been

对整体污水处理设施效率监测时，采样点应布置在（）

A、车间污水排放口

B、集水井

C、二沉池排放口

D、污水总排口