已知地球半径为R,地球自转的周期为T,地球表面的重力加速度为g,求
When we arrived, it was already midnight and the party was over.
(II)把图形B向右平移4格,得到图形C.以点O为中心,把图形C顺时针旋转90°,得到图形D.
(III)O点的位置可以用数对( )表示.