A:twice as much a
B:as twice much a
C:twice as many a
D:as twice many a
1.8的倒数是
读某省人口出生率、死亡率变化图(图甲)和人口年龄结构变化图(图乙),回答小题。
史书记载“始置诸州通判,故常与知州争权”,反映的朝代是( )
圆心角为60°,半径为4cm的扇形的弧长为 ____cm.