Question

英语句型中什么时候用do sth, to do sth, doing sth或 to doing sth 呢?

越详细越好

Answer 1

do sth 一般用于祈使句中 例如 Get away frow me !
to do sth 用于将要干什么，例如 I want to go to the shop.
doing sth 表示动作正在进行，例如I am studying.
to doing sth 中to一般是介词，用于特殊的短语中，例如在信中我们经常说的I 'm looking forward to seeing you.

Answer 2

1. (Do some sports) and you will feel better.
祈使句（do sth.） + and + 陈述句
2. Do some sports (to be healthier).
括号中动词不定式说明目的。
3. doing sth. 要么是动名词，要么是现在分词。
Watching TV sometimes is boring.
Seeing from the top of the tower, we find our city so beautiful.
4. to doing sth.就是动名词作介词to的宾语。to在很多时候都加动词原形构成动词不定式，而在类似look forward to 这样的短语后面跟动词的时候就用 doing . 比方说 I am looking forward to meeting you.