—The pollution problem here seems to get more and more serious.--Yes. Somethingabout it.A.

问题补充：

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

--Yes. Somethingabout it.

A. must do

B. must be done

C. is doing

D. had been done

答案：

A. must do

(答案→)B. must be done

C. is doing

D. had been done

解析：考查时态及语态.句意:这儿的污染问题单好像越来越严重.——是的，对此必须做些什么。下文主语是动作对象，故用被动语态，结合语境可知选B。