甲、乙两车都做匀速直线运动,两车的速度分别为15m/s和10m/s,则两车都运动10s时间后的路程之比为( )
People in Colombia needn't make plans to meet their friends. They often just drop by them.
已知抛物线y=ax2+bx+c的开口向下,顶点坐标为(2,-3),那么该抛物线有( )
一 We'll have a quiz at the end of class.
一 Study harder, and we'll do better.