大中型火力发电厂，高压厂用电系统电压等级通常选用（）。
A.3kV
B.6kV
C.10kV
D.10kV以上
参考答案：B, C
She was moving out of her old apartment _____ she suddenly realized that the key to the new apartment
wasn't on her. [ ]
A. until
B. once
C. when
D. as if
（）个链路可以聚合成快速以太网信道？
A.0
B.2
C.4
D.8
