什么叫钝角三角形?并画一个钝角三角形.
Not having __________ her daughter abroad for a long time, the mother was very worried.
照这样计算:
汽车以6m/s的速度匀速驶上长为60m的斜坡顶,接着又以10m/s的速度从坡顶沿原路匀速返回,该汽车上下坡的全程中的平均速度是( )
—Don't be shy. Believe in yourself and everything will be OK.