A.56 B.57 C.58 D.59
A.高电压大电流 B.低电压大电流 C.高电压小电流 D.低电压小电流
A.14 B.15 C.16 D.17
A.3 B.5 C.8 D.10
A.5 B.10 C.15 D.20