A:C、E两点都保持静止不动
B:图示时刻A、B两点的竖直高度差为20cm
C:图示时刻C点正处在平衡位置且向上运动
D:从图示的时刻起经0.25s后,B点通过的路程为20cm
—May I go swimming this afternoon?— I'm afraid not _______ you have finished your homework.
2004年8月,奥运会圣火在希腊的雅典点燃。从历史上来看,古代希腊是( )
一Doctor, is there anything wrong with my eyes?
一No. is OK.