一辆汽车保持恒定速率驶过一座圆弧形凸桥,在此过程中,汽车一定是( )A.做匀变速运动 B.所受合外力为零 C.加速度大小恒定 D.做变加速运动 答案:CD 解析: 略听录音,小猫迷路了,按你听到的方向送它回家吧! Go down the 1 street, turn left, then go along this street and turn 2 at the 3 street, go 4 the street and then turn 5 . You will find the cat's house.