12.7 need/want/require/worth
注意:当 need,want,require,worth(形容词)后面接doing也可以表示被动。
Your hair wants cutting.你的头发该理了。
The floor requires washing.地板需要冲洗。
The book is worth reading.这本书值得一读。
典型例题
The library needs___,but it'll have to wait until Sunday.
a.cleaning B.be cleaned C.clean D.being cleaned
答案A.need(实意)+n /to do,need(情态)+do,当为被动语态时,还可need+doing.本题考最后一种用法,选A。如有to be clean 则也为正确答案。
counldn't have done,"不可能已经"。must not do 不可以(用于一般现在时)。