—The pollution problem here seems to get more and more serious.

--Yes. Something_____about it.

A．must do

B．must be done

C．is doing

D．had been done

按运行组织划分，班轮航线可分为（）。

A.集装箱航线

B.沿海航线

C.普通杂货航线

D.多港挂靠直达航线

E.干、支线结合分程运输航线