题目

等差数列的公差为，前项和为，若，则当取得最大值时，（ ）A. B. C. D. 答案：【答案】C【解析】由可知，又，即。根据题意，等差数列中，， 则， 又由为等差数列，则，又由，则， 则当时，取得最大值，故选：C．The house rent is expensive. I've got half the space I had at home and I'm paying________ here. A. as three times much　　　　　　　　　　    B. as much three times C. much as three times　　　　　　　　　　    D. three times as much