在什么情况下要用助动词do

问题描述:

在什么情况下要用助动词do
麻烦说得简单点,最好有点例句

1.肯定句变为否定句和疑问句时,如:
They play games every day .
---->They do not play games every day .
---->Do they play games every day
Sit down .
---->Do not sit down .
2.强调动作时,如:
Please go there.
---->Please do go there.