U1234A12B23的精选

问题详情：已知全集U={1,2,3,4},*A={1,2},B={2,3},则(A∪B)=()A.{1,3,4}         B.{3,4}       C.{3}         D.{4}【回答】D.先求出两个*的并集,再结合补集概念求解,因为A={1,2},B={2,3},...