小红站在竖直放置的平面镜前2m的地方,像到小红的距离为____
A. We play basketball on the playground.
B. He likes to play on the computer.
C. Jenny likes to play with her doll.
D. We like to sing and dance(跳舞).
E. He likes to do his homework.
某商场以每件30元的价格购进一种玩具.通过试销售发现,逐渐提高售价,每天的利润增大,当售价提高到45元时,每天的利润达到最大值为450元,再提高售价时,由于销售量逐渐减少利润下降,当售价提高到60元时,每天一件也卖不出去.设售价为x,利润y是x的二次函数,则这个二次函数的解析式是( )
科学革命时期,被誉为“发现了新宇宙”的是( )
n边形的外角和与内角和的度数之比为2:7,则边数为____