1、Need，want，require，deserve(应得，值得)，be worth ，not bear(经不住)后面接doing主动表被动。
The book is worth reading.这本书值得一读。
The old building requires repairing.这座古建筑需要修了。
These young seedlings will require/need looking after (=need to be looked after) carefully.这些幼苗将需要小心的照管。
Your hair wants/needs cutting (needs to be cut)。你的头发该剪了。
2、不定式作定语，放在被修饰词后面，与前面被修饰的名词或代词有动宾关系，又在句子中与另一名词或代词有主谓关系，不定式要用主动表被动含义。
I have much work to do.我有许多要做的事情。
(与work有动宾关系，与I有主谓关系)
