体循环和肺循环的共同规律是( )
A:心房→动脉→身体各器官→静脉→心室
B:心室→动脉→身体各器官→静脉→心房
C:心房→静脉→身体各器官→动脉→心室
D:心室→静脉→身体各器官→动脉→心房
皮球从3m高处落下,被地板弹回,在距地面1m高处被接住,则皮球通过的路程和位移的大小分别是( )
— I think buyers ________ spend too much time going to shops.
如图的几何体的俯视图是( )