如何将肯定句改为否定句

如何将肯定句改为否定句

方法一

谓语动词是be、have(作“有”讲) ，或谓语动词有助动词、情态动词时，在它们的后面加not。若句中有some时，需将some改为any。例如：

I have some books on this subject.

→I have not any books on this subject.

He can speak English.

→He cannot speak English. 方法二

当谓语动词是行为动词时，而句中又没有情态动词或助动词时，需要在谓语动词之前加do not (或did not) 来构成否定句。例如：

I know something about it.

→ I don’t know anything about it.

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方法三

否定由think、believe、know等动词引出的宾语从句时，应将主句改为否定形式。例如：

She knows why the train is late.

→She doesn’t know why the train is late. 方法四

祈使句的否定形式是在谓语动词前直接加do not。例如：

Read in bed.

→Don’t read in bed. 方法五

如果肯定句是特殊句型，则要具体问题具体分析：

陈述句中含有had better时，变为否定句时，要把not加在better后。例如：

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You had better go with me.

→You had better not go with me.

陈述句中含有both (all) of ＋名词作主语时，改为否定句时，要用neither来代替both，none代替all。并注意谓语动词数的变化。例如：

Both of them are Americans.

→Neither of them is American.

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