常用10KV油浸式配电变压器的无载调压开关相邻档电压调整范围是（）。
A、2.5%
B、5%
C、7.5%
D、10%
参考答案：B
鸡有3020只，鸭的只数比鸡多一些，鹅的只数比鸡少一些，兔的只数比鸡少得多，（ ）最少．
A．鸡
B．鸭
C．鹅
D．兔
Tom hid himself behind the door, _________ he could hear the steps of his mother clearly.
A．from which
B．from where
C．where
D．which
