句型变换复习·肯定句变否定句

句型变换复习·肯定句变否定句

1. 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.

2. 当谓语动词是行为动词，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, does not或did not 来构成否定句。例如

I know something about it.

→ I don’t know anything about it.

3. 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.

4. 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.

5. 特殊句型

陈述句中含有had better，要将其变为否定句时，要把not加在better后。例如

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，要将其改为否定句时，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.