以保持短语动词的完整性，如：She always takes good care of the children. →The children are always taken good care of. （５）含有情态动词的动词改为被动语态时是将情态动词后面的动词原形改为被动语态，因其前有情态动词，所以构成被动语态的助动词be就要使用原形，如：They must finish the work before Friday. →The work must be finished before Friday.（６）be going to, be to, used to, have to和had better等结构，其作用相当于情态动词或助动词，在改为被动语态时，只需将后面的动词原形改为被动语态即可，如：The are not going to put off the football match. →The football match is not going to be put off.The house facing the lake is in the possession of John.=The house facing the lake is possessed by John.The question is under discussion .=The question is being discuss

【重点提示】 英语中有时用主动形式表示被动含义，主要有以下三种情况：谓语动词、非谓语动词和介词短语。

{C}<!--[if !supportLists]-->(一) {C}<!--[endif]-->用谓语动词的形式表

示被动含义

1．表示状态特征的连系动词look , sound , feel ,smell , taste , prove, appear+形容词/ 名词构成的系表结构。

The steel feels cold. His plan proved (to be )practical .

2.表示“开始”、“结束”、“运动”的动词，如begin , finish , start , open , close , stop , end , shut , run, move.

Work began at 7 o’clock this morning . The shop closes at 6 p.m. every day .

3.表示主语的某种属性特征的动词，如read, write ,act , sell , wash , clean ,open , cook,lock ,shut ,dry ,eat , drink.这类动词一般不单独使用，常加上一个修饰语。如：This coat dries easily . The pen writes smoothly.

4.少数动词用于进行时，其主动形式表示被动含义。如 ：print , build , cook , fry , hang ,make .The books are printing .

（二）用非谓语动词的主动形式表示被动含义

1．want , need , require 作“需要”讲时，后用动名词的主动形式表被动含义，这时动名词同句子的主语之间在逻辑上有动宾关系。如：The house needs / wants / requires repairing .

2．形容词worth 后用动名词的主动形式表示被动含义 This problem is well worth considering .

3．不定式在某些形容词（difficult ,easy ,hard ,comfortable , pleasant , fit ,unfit , light , heavy ,good , safe ,dangerous ）后作状语且和句子的主语（或宾语）构成逻辑上的动宾关系时，用主动形式表示被动含义，这是因为人们往往认为形容词后省去了for sb. 如：The question is difficult (for me )to understand . She is easy (for people )to get along with .

4．不定式作名词的后置定语，与被修饰的名词构成逻辑上的动宾关系，又和该句的主语后宾语构成逻辑上的主谓关系时，不定式常用主动式表被动含义。如：I have a lot of work to do this evening .

{C}<!--[if !supportLists]-->4． {C}<!--[endif]-->在there be 句型中修饰

主语的动词不定式用主动形式和被动形式皆可。在口语中多用主动形式。如： There are many things to do / be done .