综合类考试：重点语法知识点详解被动语态
不知道或没必要提到动作的执行者是谁时用被动语态。强调或突出动作的承受者常用被动语态(by短语有时可以省略)。
(二)被动语态的构成方式：
be 过去分词，口语只也有用get / become 过去分词表示。
(三)被动语态的基本用法：
(1)使用被动语态时应注意的几个问题。
①主动变化被动时双宾语的变化。看下列例句。
My friend gave me an interesting book on my birthday.
An interesting book was given to me(by my friend)on my birthday.
I was given an interesting book (by my friend)on my birthday.
②主动变被动时，宾补成主补(位置不变)；(作补语的)不定式前需加to.
The boss made him work all day long.
He was made to work all day long(by the boss)
③短语动词变被动语态时，勿要掉“尾巴”。
The children were taken good care of (by her)。
Your pronunciation and spelling should be paid attention to.
④情态动词和be going to、be to、be sure to、used to、have to、had better等结构变被动语态，只需将它们后面的动词原形变为be 过去分词。
⑤当句子的谓语为say、believe、expect、think、know、write、consider、report等时，被动语态有两种形式：(A)谓语动词用被动语态，动词不定式作主补。(B)用it作形式主语，真正的主语在后面用主语在后面用主语从句来表示。如：
People say he is a smart boy.
It is said that he is a smart boy.
He is said to be a smart boy.
People know paper was made in China first.
It is known that paper was made in China first.
Paper was known to be made in China first.
类似句型有：It is said / known / suggested / believed / hoped/ thought that …
①所有的不及物动词或不及物动词词组不能用于被动语态之中。
②表示状态的谓语动词，如：last、hold、benefit、contain、equal、fit、join、mean、last、look like、consist to等。