英语中什么时候用do和does
1、do和does可以用作实义动词，在一般现在时肯定句中，其中does用在第三人称单数，do用在其它人称中，如：
He does his homework everyday.
I do excercise every Fridday.
2、do和does可以用作助动词，完成一般现在时的问句及回答和否定句中，其中does用在第三人称单数，do用在其它人称中，如：
Do you love me?/No, I don't.
Does he go to school everyday?/Yes, he does.
What do you do on Satudays?(第一个do)
What does he do every morning?
I don't like snakes.
He doesn't want to study English.
3、do可以作为实义动词，代替所提问的.动作，用在特殊疑问句的各时态中，如：
How do you do?（第二个do）
What did you do last night?