地球是一个____ 的球体,它的平均半径是____ 千米.
如图,已知AB是圆O的直径,AB=4,C为圆上任意一点,过C点做圆的切线分别与过A,B两点的切线交于P,Q点,则CP•CQ=____
____是生物体结构和功能的基本组成单位.
— Have you got the results of the final exam?
— Not yet. It will be a few days ______ we know the full results.
____