EPON上行时,每个ONU在由ONU各自确定的时隙中发送数据帧。
参考答案:错
—What he did made me _____ unhappy.
—Oh, really? What did he do? [ ]
A. feel
B. feels
C. to feel
D. feeling
如图甲所示电路中,电流表A1与A2指针指示的位置均为图乙,求:
(1)电流表A1的读数是多少;(2)电流表A2的读数是多少;(3)通过灯L1电流是多少.