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English definition of “know”

know

verb (HAVE INFORMATION)    /nəʊ/ US  /noʊ/ (knew, known)
A1 [I or T, not continuous] to have information in your mind: "Where did he go?" "I don't know." "What does it cost?" "Ask Kate. She'll know." She knows the name of every kid in the school. I don't know anything about this. [+ question word] We don't know when he's arriving. I don't know (= understand) what all the fuss is about. [+ (that)] I just knew (that) it was going to be a disaster. She knew (= was aware) (that) something was wrong. [+ obj + to infinitive ] Even small amounts of these substances are known to cause skin problems.formal The authorities know him to be (= know that he is) a cocaine dealer.Knowing and learning A1 [T not continuous] used to ask someone to tell you a piece of information: Do you know the time? [+ question word] Do you know where the Post Office is?Knowing and learning A2 [I or T, not continuous] to be certain: [+ (that)] I know (that) she'll be really pleased to hear the news. [+ question word] I don't know whether I should tell her or not. The party is at Sarah's house as/so far as I know (= I think but I am not certain).Knowing and learning Grammar:KnowWe commonly use the verb know with a noun phrase, with a that-clause or with a wh-clause (e.g. who, where, why):See moreGrammar:Know how + infinitiveWe do not commonly use know + to-infinitive. We use know how + to-infinitive:See moreGrammar:Know + object + infinitiveIn very formal English, we use know + object + to-infinitive:See moreGrammar:Know without an objectTo refer to general knowledge, we use know without an object:See moreGrammar:You knowWe use you know very often in speaking as a discourse marker. We use it to check that the people we are speaking to share the same knowledge as us and understand what we are saying:See more
(Definition of know verb (HAVE INFORMATION) from the Cambridge Advanced Learner's Dictionary & Thesaurus © Cambridge University Press)
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