题目

已知某扇形的面积为，若该扇形的半径，弧长满足，则该扇形圆心角大小的弧度数是（）A. B. C. D.或 答案：【答案】D【解析】由扇形的面积公式构造关于，的方程组，解出方程，由圆心角即可算出圆心角大小的弧度数。据题意，得解得或所以或.故选D.8. (2015 •广东广州) The stories were written by Mark Twain are often humorous.   A. that   B. those   C. who   D. what