1. be動詞的否定式
be 動詞根據(jù)不同的人稱和時態(tài)有不同的形式，在一般現(xiàn)在時中是am ， is ， are可用作聯(lián)系動詞，構(gòu)成否定式時，一律在其后面加否定詞not.
He is reading. --- He is not reading. They are from China. --- They are not from China.
2. 情態(tài)動詞的否定式
情態(tài)動詞的否定式是在其后面直接加not. 如：
I can swim. --- I can’t swim. He can dance. --- He can’t dance. You should go to school at seven. --- You shouldn’t go to school at seven.
3. 實義動詞的否定句
實義動詞變否定句時，要借助助動詞do ， does，在一般現(xiàn)在時中用do或者does其句子結(jié)構(gòu)為：主語+ don’t / doesn’t + 動詞原形+其它 例如：
I like pop music. --- I don’t like pop music. He likes running. --- He doesn’t like running.
She does her homework at home. --- She doesn’t do her homework at home
be 動詞根據(jù)不同的人稱和時態(tài)有不同的形式，在一般現(xiàn)在時中是am ， is ， are可用作聯(lián)系動詞，構(gòu)成否定式時，一律在其后面加否定詞not.
He is reading. --- He is not reading. They are from China. --- They are not from China.
2. 情態(tài)動詞的否定式
情態(tài)動詞的否定式是在其后面直接加not. 如：
I can swim. --- I can’t swim. He can dance. --- He can’t dance. You should go to school at seven. --- You shouldn’t go to school at seven.
3. 實義動詞的否定句
實義動詞變否定句時，要借助助動詞do ， does，在一般現(xiàn)在時中用do或者does其句子結(jié)構(gòu)為：主語+ don’t / doesn’t + 動詞原形+其它 例如：
I like pop music. --- I don’t like pop music. He likes running. --- He doesn’t like running.
She does her homework at home. --- She doesn’t do her homework at home