题目

— How was your recent visit to Qingdao?— It was great. We visited some friends，and spent the ___days at the seaside. A . few last sunny B . last few sunny C . last sunny few D . few sunny last 答案：B 在等比数列{an}中，Sn表示前n项和，若a3＝2S2＋1，a4＝2S3＋1，则公比q等于 [　　] A． 3 B． －3 C． －1 D． 1