交流输电线路的主要参数包括（）。
A.串联电阻
B.串联电抗
C.并联电导
D.并联电容
参考答案：A, B, C, D
用双线桥法标明反应2KMnO4+5Na2SO3+ 3 H2SO4=K2SO4+2MnSO4+5Na2SO4+3H2O的电子转移的方向和数目__________________。
I really don’t know ___________.
A．how they’ve got so angry with me.
B．why have they got so angry with me.
C．how have they got so angry with me.
D．why they’ve got so angry with me.
