A:①②
B:①③
C:③④
D:②③
已知集合A={x|y=2x-x2},B={y|y=2x,x>0},R是实数集,则(∁RB)∩A= ____.
_We'd better ask her to play games with us.
①背景 ②军事行动 ③阶段性成果 ④失败原因
能使人体内静脉血变成动脉血的过程发生在( )