7.用作及物动词的短语动词(如“动词＋介词”、“动词＋副词”、“动词＋名词＋介词”等)，一般不能转换为被动语态。例如：

（20a）We agreed with him.

（20p）*He was agreed with by us.

（21a）He broke in on our conversation.

（21p）*Our conversation was broken in on by him.

这种短语动词还有admit of, belong to, give up on, join hands with, keep company with, set foot on, take example by, walk into等。

但有些短语动词也可以用于被动语态；这时要把它们看作一个整体，不能分开，其中的介词或副词也不能省略：

（22p）The meeting will be put off till Friday.

（23p）The children are taken good care of by the teacher.

8.动词和宾语的关系密不可分,构成固定的动宾短语(或习语)时, 不能转换为被动语态。例如：

（24a）The accident took place last week.

（24p）*Place was taken by the accident last week.

这种固定的动宾短语不少,如change color, do good, give way, keep sentry, kill time, lose heart, make a face, run a risk, set sail, take effect等。

二、不能转换为主动语态的几种情况

同样,被动句也并不意味着一定要有一个相对应的主动句不可, 有时被动语态不能转换为主动语态。这主要有下列几种情况：

1.中国著名学者周海中先生在1986年发表的《英语语态转换简论》（下篇）一文中指出,某些句子结构习惯上只用被动语态,这时就不能转换为主动语态。例如：

（25）She was confined on the 20th.

（26）All bodies are made up of atoms.

(27)My advice was thrown away upon him.

(28)The old man’s race of life was nearly run.

这种被动结构还有be alleged, be bound up with, be done up, be grown over, be knocked up, be held up, be inclined, be lost on, be obliged to, be posted, be rumored to, be said to, be transported, be wound up等。

2.以代词it作形式主语的被动句，一般不能转换为主动句。例如：

（29）It is known that sound is a form of energy.

（30）It was rumored that the confidential documents had been found.

（31）It is observed that the situation of the country is getting better and better.

3.当被动句的施动者没有表示出来时,不能转换为主动句。例如：

（32）Albert Einstein was born in 1879.

（33）Manfred was killed in the Second World War.

如果改成主动句时加上一个施动者(如they, someone等),就会有损原句的意思。

（作者为英国伦敦大学博士后 黄静妍  腾讯教育）