U1234567Axx的精选

问题详情：已知全集U={1,2,3,4,5,6,7},A={x|x≥3,x∈N},则∁UA等于()(A){1,2}      (B){3,4,5,6,7}(C){1,3,4,7}   (D){1,4,7}【回答】A解析:因为U={1,2,3,4,5,6,7},A={x|x≥3,x∈N}={3,4,5,6,7},所以∁UA={1,...