陈述句变为否定句
1.如果陈述句中有be动词（am , are, is, was, were）,就在be动词后
面直接加not。

I am a student. → I am not a student.
You are sad. → You are not sad.
She is a good girl. → She is not a good girl.
He is a good boy. → He is not a good boy.
Yesterday was Monday. → Yesterday was not Monday.
The students were busy yesterday.
→ The students were not busy yesterday.
2.如果陈述句中有情态动词（can must should may will等），就在情
态动词后面直接加not。

I can swim. →I can not swim.
You will go to the park. → You will not go to the park.
3.如果陈述句中没有be动词也没有情态动词（就是实意动词），就
需要借助助动词（do, does, did）来帮助否定。

①当句中的动词是原形时，加don’t
I like English. → I do not like English.
You have dinner. → You do not have dinner.
②当句中的动词是第三人称单数时，加doesn’t ，再加动词原形
She likes singing. →She doesn’t like singing.
She does her homework. → She does not do her homework. (特例)
③当句中的动词是过去式时，用didn’t，加动词原形
We had a great time during our holidays.
→We did not have a great time during our holidays.
I went to school yesterday.
→I did not go to school yesterday.
4、陈述句中的some在否定句中应改为any
如：There are some students in the classroom.
There are not any students in the classroom.。