10KV高压隔离开关合闸时，三相动闸刀与静触头同时接触，各相前后相差（）才算合格。
A.2mm
B.2.5mm
C.3mm
D.4mm
参考答案：D
When she heard the strange news, a ___ look ___ in her face.
A．puzzling; appearing
B．puzzled; appeared
C．puzzling;appeared
D．puzzled; appearing
（）不属于华北区的五大山水地质观。
A.华北平原、黄土高原
B.太行山斜坡断裂带、古老的中原文化
C.川藏高原
D.最古老的岩石组成的名山
