Maria came ____ (猛冲,突进) down the stairs as soon as she heard her mother back home.
矩形、菱形、正方形都具有的性质是( )
如图所示,甲、乙两质点沿各自轨迹由O点出发,最后均到达A点, 下列说法正确的是 ( )
环境为人类提供的资源是( )