下列所示的四个图形中,∠1和∠2是同位角的是( )
A:②③
B:①②④
C:①②③
D:①④
一质点做匀加速直线运动,初速度为2m/s,加速度为5m/s2,试求该质点:
— Where is your sister, Dick? I need her help.— Dad, she in her room. Let me help you instead.
下列各组地形区中均位于我国西北地区的是( )