Question

i want to buy a computer改为否定句

Answer 1

I want to buy a computer改为否定句：I dont  want to buy a computer.be动词的否定式

动词的否定变化

 1、实义动词的否定句

实义动词变否定句时，要借助助动词do , does，在一般现在时中用do或者does其句子结构为：主语+ don’t / doesn’t + 动词原形+其它 例如：

（1）I like pop music. --- I don’t like pop music. 

（2）She does her homework at home. --- She doesn’t do her homework at home

2、be 动词根据不同的人称和时态有不同的形式，在一般现在时中是am , is , are可用作联系动词，构成否定式时，一律在其后面加否定词not。

（1）He is reading. --- He is not reading. 

（2）They are from China. --- They are not from China.

3、情态动词的否定式

情态动词的否定式是在其后面直接加not。 如：

（1）I can swim. --- I can’t swim. He can dance. --- He can’t dance. 

（2）You should go to school at seven. --- You shouldn’t go to school at seven.