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.formalThe authorities know him to be (= know that he is) a cocaine dealer.Knowing and learningA1[Tnot 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 learningA2[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