非谓语的问题....1.needtobedone与needdoi
1.ne to be done 与need doing，表被动语态，那么他们两个有什么区别？
need doing = need to be done 前者是主动表被动 例如： the plants need watering=the plants need to be watered 类似的： need, want, require, worth（形容词）后面也可以加doing表被动