如图所示,绕过定滑轮的轻绳拴在小车上,另一端吊一物体,若小车沿水平向前匀速运动,则物体的运动状态为( )
A:向上做加速运动
B:向上做匀速运动
C:向上做减速运动
D:无法确定
A. B.
C. D.
①____ ②____ ③____ ④____
— Jim's mother dislikes cartoons in the Past, but now she likes to watch them with little Jim.
— Oh, just as the saying goes, .