It ________ me that I could buy the admission ticket of the exhibition at the discount of 50% with my student card, ________ made me extremely excited.

A．happened to; that

B．occurred to; it

C．happened to; which

D．occurred to; which

大车（）继电器整定值调得偏小，可导致天车掉闸。

A、电压

B、过电流

C、时间

D、中间