题目

设等差数列的前n项和为，且满足，，则，，，，中最大项为 A. B. C. D. 答案：【答案】C【解析】试题分析：因为S19>0，S20<0，所以，且所以，所以，当时，所以，中最大项为，故选C． They can ________ behavior from their daughter but not anyone else． [　　] A．get along with B．come up with C．make contact with D．put up with