题目

下列函数既是偶函数又在区间上单调递增的是（ ）A. B. C. D. 答案：【答案】D【解析】根据函数的奇偶性及单调性一一判断即可.解：易判断为非奇非偶函数，故A选项不正确；是奇函数，故C选项不正确；是偶函数但在单调递减；故B选项不正确；对于函数，易判断是偶函数，对其求导得，当时，故；当时，，故仍有，则对恒成立，即满足在单调递增．故选：D． Thousands of children                said they were forced to practice the piano.     A. to question              B. to be questioned           C. questioned          D. questioning