A:地球是一个两极稍扁、赤道略鼓,不规则的球体
B:地球的赤道周长约4万千米
C:地球的平均半径约2万千米
D:地球的表面积约5.1亿平方千米
6×3=____ 1×6=____ 6×4=____ 6×2=____ 6×6=____
— I haven't got the reference book yet, but I'll have a test on the subject next month.
— Don't worry. You _______ have it by Friday.