架空线路发生带地线合闸或线路倒杆、造成的故障一般为（）。
A.三相短路
B.两相短路
C.单相接地
D.缺相
参考答案：A
She brought with her three friends，none of ________ I had ever met before.
A．them
B．who
C．whom
D．these
