12.7 need/want/require/worth-动词的语态
12.7 need/want/require/worth
当 need, want, require, be worth背面接doing时，默示的是主动意义。例如：
Your hair wants cutting.你的头发该理了。
The floor requires washing.地板需要冲洗。
典范例题
The library needs___, but it'll have to wait
until Sunday.
A. cleaning B. be cleaned C. clean D. being cleaned
谜底 A. need（实意） +n /to do，need（模样形状）+
do，当为主动语态时，还可need + doing.本题考末了一种用法，选A。如有to be cleaned则也为准确谜底。