—Why were you so late this morning?

—I _____ in heavy traffic for an hour on the way here.

A．have been caught

B．have caught

C．had caught

D．was caught

在分区所、AT所、开闭所内由27.5kV三相自用变压器（）供电，10kV单相自用变压器仅给其中的一段380/220V交流母线供电。

A、主

B、备用

C、全