1. 其后一般不直接跟不定式,但在以下情况可接不定式:
(1) 后接“疑问词(why 除外)+不定式”。如:
I didn’t know what to say. 我不知道说什么。
We don’t know when to start. 我们不知道什么时候出发。
他会弹钢琴。
误:He knows to play the piano.
正:He knows how to play the piano.
(2) 表示知道应该要做某事。如:
She knows not to tell anyone about it. 她知道不该告诉任何人。
比较下面两句,注意其中的how的有无和意思的变化:
Does he know to come here first? 他知道应该先到这儿来吗?
Does he know how to come here? 他知道如何到这儿来吗?
2. 比较 know 与 get [come] to know:前者意为“认识”,是持续性动词;后者意为“开始认识”,是终止性动词。如:
We’ve known each other for 10 years. 我们俩认识10年了。
We got to know each other ten years ago. 我们俩是10年前认识的。
3. know 之后可接不定式的复合结构,主要句型为:
(1) know+宾语+to be(to be通常不省略),这类句型可转换为that引导的宾语从句。如:
I know him to be a fool.=I know (that) he is a fool. 我知道他是个傻瓜。
(2) know+宾语+to do(有时可省略 to),在这类句型中 know 一般只限于用过去时或完成时,通常译为“听说过”“见过”等。如:
I have never known her (to) tell lies. 我从未听说她撒过谎。
I’ve never known her (to) be late before. 我以前从不知道她迟到过。
在被动语态中,不定式必须带 to。如:
He was known to have a quick temper as a boy. 人们都知道他在孩提时代脾气暴躁。
4. 比较:be known as, be known for 与 be known to:
(1) be known as 意为“作为……出名”。如:
She was well known as an excellent dancer. 她作为一个杰出的舞蹈家非常有名。
(2) be known for 意为“因为……出名”。如:
He is known for his poems. 他以他的诗出名。
(3) be known to 意为“为……所知”。如:
He is known to everyone. 大家都熟悉他。
追问do you know to find a man 这样行不