RFID卡（）可分为：主动式标签（TTF）和被动式标签（RTF）。
A、按供电方式分
B、按工作频率分
C、按通信方式分
D、按标签芯片分
参考答案：C
It is the film _______ director is Steven Spielberg _______ attracts quite a few viewers throughout the world.
A．that; who
B．which; that
C．whose; that
D．whose; who
少量CO＋CO2的脱除方法有哪几种？
