—How are you?
—Fine, ______.[ ]
A. thank
B. thanks
C. OK
答案：B
—Could you help me _____my English, Jack? —No problem.
A. with B. in C.at
电力系统的电抗是因导线中通过（）电流而使导线周围产生交变磁场所引起的。
A.直流
B.交流
C.雷击
D.内过电压
