know后面加to

know +sb/sth或者know+that从句，know后面一般不接不定式或者分词作宾语，一般都是接that从句，that可省略。

know后面加doing还是todo

know加how to do可以,没见过直接加to do sth.或doing sth一般是直接加名词know 作 “见到过；听到过”[一般用于过去时或完成时]：但不是固定know+to do sth 固定句型I've never known him to cry.我从未见过他哭泣.

think作谓语,一般也是加宾语或从句作“料想；猜想；相信”意,可以像下面那样翻译,但不是think + to do sth 的固定句型I didn't think to see my boss in the party.我没想到会在聚会上见到我的老板.

know的例句

‘What's the answer?’ ‘I don't know.’

“答案是什么？”“我不知道。”

‘There's no one in.’ ‘ How do you know? ’

“里边一个人都没有。”“你怎么知道呢？”

You know about Amanda's baby, don't you?

你知道阿曼达的小宝宝吧？

I don't know about you, but I'm ready for something to eat.

不管你怎么样，反正我要吃点东西。