单项选择题
A.9BarB.8.5BarC.8BarD.7.5Bar
A.8Bar和10BarB.8.5Bar和10BarC.8.5Bar和9BarD.8Bar和9Bar
A.17.5-27.5KVB.21.5-27.5KVC.21.5-31KVD.17.5-31KV