某汽车启动和到达的时刻及对应的里程表(表盘指示为千米数)示数如图所示,则汽车行驶的平均速度是 ____ km/h.
函数y=12x2-lnx的单调递减区间为( )
As we grow up, it always _______ that after we give something up, we gain something new in its place. ( )