, want, require(要求,需要), deserve(应得,值得 ), be worth值得), not bear(经不住 ) +doing主动表被动。Eg. 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)Tom is looking for a room to live in. Tom在找一间住的房间。(与 room 有动宾关系,与Tom 有主谓关系)He has a family to support.他要维持一个家庭。(与 family有动宾关系,与he 有主谓关系)3. 不定式修饰作表语和宾语补足语的形容词时,结构:主语 +系动词 +形容词 + 不定式; 动词+宾语 +形容词 +不定式。如果形容词是表示难易、利弊等含义,如difficult, easy, comfortable(舒适的 ), convenient(便利的,方便的), hard, cheap, expensive, 等,不定式用主动表被动。The question is difficult to answer. 这个问题很难回答。The work is easy to do. 这项工作很好做。I found the car comfortable to ride in. 我觉得这种车很好坐。That makes poetry difficult to write. 那就使得诗很难写。4. 在 be to 结构中的一些不定式: 这种结构中的不定式通常应用主动表被动。下列动词用不定式的主动形式表示被动意义:Who is to blame for starting the fire?这场火灾应由谁负责?You are to blame for the accident. 你应为这事受动责备。The house is to let. 此房出租。A lot remains to do.还剩下许多事情要做。5. 系动词没有被动形式, 但有些系动词常表示被动意义。常见的有taste(吃起来 ), sound ( 听起来 ), prove( 证明是 ), feel( 摸上去感到 ), look( 看起来 ) ,smell( 闻起来 ) 等,例如 :Your reason sounds reasonable.你的理由听起来很合理。Good medicine tastes bitter to the mouth.良药苦口...