1.不及物动词无被动语态。
The dinosaurs disappeared about 65 million years ago.
2.有些动词用主动形式表示被动意义。这些动词主语以物居多，谓语动词一般表示主语的性质和特征。这类动词有许多，如: write, break, selld等。
This pen writes well.
This new book sells well.
3.感官动词或使役动词使用省略to的动词不定式，主动语态中不带to ，但变为被动语态时，须加上to 。 感官动词有smell,sound,taste,fell等。使役动词有let,make,have,help,hear,see,watch,notise,look,listen.
例：make somebody do something→somebody+ be +made to do something
see somebody do something→somebody +be +seen to do something
A girl saw my wallet drop when she passed by.→My wallet was seen to drop by a girl when she passed by.
The boss made the little boy do heavy work.→The little boy was made to do heavy work by the boss.
His mother gave him a present for his birthday.→ He was given a present by his mother for his birthday.
4.如果是接双宾语的动词改为被动语态时，直接宾语(物)作主语，那么动词后要用介词，这个介词是由与其搭配的动词决定。
He gave me a book.→A book was given to me by him.
He showed me a ticket.→A ticket was shown to me by him.
My father bought me a new bike. →A new bike was bought for me by my father.
5.一些动词短语用于被动语态时，动词短语应当看作一个整体，而不能丢掉其中的介词或副词。
We can't laugh at him. →He can’t be laughed at by us.
He listens to the radio every day. →The radio is listened to by him every day.
The nurse is taking care of the sick man. →The sick man is being taken care of by the nurse.
6.一些表示状态的动词没有被动语态。如：have, belong to等。
