—Can Li Hua help me with my English?

—I regret to tell you that her English is _____ yours. Why not ask others for help?

A．as good as

B．no more than

C．no better than

D．as much as

变压器差动保护的不平衡电流产生原因包括（）。

A、变压器各侧流变型号不同引起；

B、改变变压器分接头引起；

C、短路电流的非周期分量引起；

D、励磁涌流引起。