如图,在△ABC中,∠ACB=90°,AC=BC,E、F为线段AB上两动点,且∠ECF=45°,过点E、F分别作BC、AC的垂线相交于点M,垂足分别为H、G.
— I saw Mr. Green at school this morning.
— No, it _____ him. He flew to Canada last week.
一个做初速度为零的匀加速直线运动的物体,1秒内的位移和3秒内位移的比为( )
Everyone____ at the party yesterday.