单位卡不允许存取现金。
参考答案：对
—So hot in the classroom. Would you mind _____ the windows?
—No. I'll do it right now. [ ]
A. not closing
B. not opening
C. closing
D. opening
A．U=vBl，流过固定电阻R的感应电流由b到d
B．U=vBl，流过固定电阻R的感应电流由d到b
C．U=vBl，流过固定电阻R的感应电流由b到d
D．U=vBl，流过固定电阻R的感应电流由d到b
vBl
vBl