—Are you sure this is a photo , the famous comedy actress?
—It surprised you, didn't it? But she was once really thin.
A:Jia Ling
B:Jia Ling's
C:of Jia Ling
D:of Jia Ling's
可持续发展的含义为 ( )
如图所示,当汽车通过拱桥顶点的速度为10米/秒时,车对桥顶的压力为车重的 34 ,如果要使汽车在粗糙的桥面行驶至桥顶时,不受摩擦力作用,则汽车通过桥顶的速度应为(g=10m/s2)( )
下列情况中的物体可以看作质点的是( )