题目

一个球的内接正四棱柱的侧面积与上下底面积之和的比为4∶1，体积为,则这个球的表面积是(    )A.12              B.π             C.12π           D.π 答案：答案:C解析:设正四棱柱的底面边长为a,高为b,则解得∴2R=.∴R=.∴S球＝4πR2=12π.Don't go out now, Julia.It is raining ________ outside.A. hardly B. heavily C. luckily