knowsthfromsth
—phrasal verbwithknowverbuk/nəʊ/us/noʊ/knew|known
toknowthedifferencebetween two things andthereforebeabletorecognizeeither, usedespeciallytomeanthat you have a goodknowledgeandunderstandingof aparticularsubject
辨别；识别
Computerexpert? He doesn'tknowamousefrom amodem!(= Heknowsnothing aboutcomputers.)电脑专家？他连鼠标和调制解调器都分不清！