下列说法不正确的是 [ ]
A.两直线平行，同位角相等
B.两点之间直线最短
C.对顶角相等
D.半圆所对的圆周角是直角
答案：B
Take the note as a reminder_________ you forget to buy some sweets for the kids while shopping there.
A．so that
B．even if
C．in case
D．as if
低压电磁开关衔铁噪声大的原因有（）。
A.两接触面磨损严重或端面上有灰尘、油垢
B.短路环损坏脱落
C.电路有电磁谐振
D.吸引线圈上所加的电压太低
