题目

已知集合A={-1,3,2m-1},集合B={3,m2}.若BA，则实数m=______ 答案：1 解析:∵BA,∴m2=2m-1或m2=-1(舍去). ∴m2-2m+1=0,(m-1)2=0.∴m=1. Don’t cut your hair. I like it _______ it is. A. before                 B. because             C. as                     D. after