接不带to的不定式(也称秃头不定式)做宾补的词改成被动时要加to.

　　常用的动词有(十个半动词)

　　一感 feel

　　二听 listen to/hear

　　三让 make/let/have

　　四看 watch/see/look at/notice

　　半帮助 help (即可用to也可不用)

　　Did anyone see Tom enter the room? →Was Tom seen to enter the room?

　　The teacher makes us do a lot of homework. → we are made to do a lot of homework by the teacher.

　　My house is full of dust because the old house just opposite ______. (2005/4)

　　will be pulled down

　　has to be pulled down

　　C. has pulled down

　　D. is being pulled down

　　D