The classroom is so dirty that it needs badly.A. cleanB. to cleanC. being cleaned D. clean

问题补充：

The classroom is so dirty that it needs badly.

A. clean

B. to clean

C. being cleaned

D. cleaning

答案：

A. clean

B. to clean

C. being cleaned

(答案→)D. cleaning

解析：考察非谓语动词.句意:教室太脏了,很需要打扫一下.动名词表示抽象动作,一般不用被动语态.故选D.