The classroom is so dirty that it needs ________ badly.

A.clean

B.to clean

C.being cleaned

D.cleaning

答案及解析： D

解析：

sth. needs/wants/requires doing/to be done为固定句式，表示“某物需要……”，主语sth与宾语doing/to be done是逻辑上的动宾关系。