A.6个                   B.8个                   C.12个                D.16个

已知集合A={1,2,3,4},B={x|x=n²,n∈A},则

A∩B=(　　)

A.{1,4}                 B.{2,3}

C.{9,16}                    D.{1,2}

A.5个                B.10个               C.20个               D.25个

设集合A={1,2,3}，B={4,5}，C={|=}，则C中元素的个数是

    A．3                B．4                C．5                D． 6

已知集合A={1,2,3,4},B={y|y=,xA},则AB=

A． {1,2,3,4}         B．{1,2}             C． {1,3}            D． {2,4}