It wants_____the classroom!A.to clean B.cleaning C.clean D.cleans为什么要选B.
问题描述：
It wants_____the classroom!A.to clean B.cleaning C.clean D.cleans
为什么要选B.
答
根据句意，课室要清洁了。动词+ing表此意，与need+doing相仿。
答
want doing是以物为主语,表示被动.和need有点像,need doing 也是以物为主语,比如My car need repairing.车需要被修理.
这道题是教室要被打扫.
want/need/require+doing都是表被动的意思.