We have bought a new computer.
→A new computer has been bought. (正确)
→A new computer have been bought. (错误)
My uncle gave me a present on my birthday.
→I was given a present on my birthday.
→A present was given to me yesterday.
3) 由动词+ 介词或副词构成的短语动词，要把它们作为整体看，即把它们看成一个及物动词，介词或副词不可拆开或漏掉。
The patient is being operated on.
The problem is solved. It needn't be talked about.
His request was turned down.
The sports meet will be put off because of the bad weather
We always keep the classroom clean.
→The classroom is always kept clean.
She told us to follow her instructions.
→We were told to follow her instructions.
注意：在see, watch, hear, notice, listen to, look at, make, feel等动词后作宾语补足语的动词不定式都不带 to，但改成被动语态后必须还原to。
We often hear him play the guitar.
→He is often heard to play the guitar.
5)当主动句的主语是nobody, no one等含有否定意义的不定代词时，被动句中将其变为anybody, 作by的宾语，并将谓语动词变为否定的被动语态。
Nobody can answer this question.
误：The question can be answered by nobody.
正：The question can not be answered by anybody.
6)当否定句中的宾语是anything, anybody, anyone等不定代词时，在被动句中应将其分别变为nothing, nobody, no one作主语，并将谓语动词变为肯定的被动语态。
They haven't done anything to make the river clean.
误：Anything hasn't been done to make the river clean.
正：Nothing has been done to make the river clean.
Who wrote the story?
误：Who was the story written?
正：By whom was the story written?
8)有些动词既是及物又是不及物，当它们和well, badly, easily等副词连用时，表示主语内在品质或性能，是不及物动词，用主动表示被动，这时不用被动语态，常见的有：write, read, clean, sell, wash, cook 等。
The cloth washes easily. 这布很好洗。
The new product sells well. 这新产品很畅销。
The books sell well. 这些书销量很好。
①感官系动词一般用主动形式表示被动意义，如：feel，look, seem, taste, sound。
— Do you like the material?
— Yes, it feels very soft.
②不及物动词没有被动语态，如：rise, happen, succeed, remain, lie等。
When we got to the top of the mountain, the sun had already risen.
After the earthquake, few houses remained.
I taught myself English.
误：Myself was taught English.
We love each other.
误：Each other is loved.