卓越教育老师整理了相关资料以供参考。
助动词（do, does ）的用法
只有实意动词作谓语时才涉及使用助动词。以like为例：
1）当句子为肯定句时不涉及使用助动词，只涉及"主谓一致"原则。
eg : I like English a lot.
Michael likes Chinese food very much.
2）当句子为否定句时，要根据主语的人称来决定使用相应的助动词：当主语为"三单"时，要使用does;当主语为"非三单"时，用助动词原形do。例如把下列句子变否定句：
Kangkang likes math.----Kangkang doesn't like math.
They like sports.------They don't like sports.
3）当句子变疑问句时，同样要根据句子的主语来决定在句首使用Do或Does.例如下列句子变问句：
Michael likes Chinese Food.----Does Michael like Chinese food? Yes, he does./ No, he doesn't.
Jane and Helen like music.----Do Jand and Helen like music? Yes, they do./ No, they don't.
