题目

阅读理解 Bargainhunters spent a record of 168.2 billion yuan ($25.3 billion; 21.7 billioneuros; ￡19.3 billion) during the 2017 Singles Day on Nov. 11, the world'slargest daylong discount festival, as e-commerce giant Alibaba Group tookonline shopping to offline stores and beyond(超越) thenation's borders(边界). Spendingclimbed by 39.3 percent during this year's sale, as consumers from 225countries and regions scooped up goods from 140,000 brands (品牌)that offered promotions during the annual event. Alibabasurpassed last year's 120.7 billion yuan total shortly after 1 pm, as overse10．已知Sn是等比数列{an}的前n项和，a2=2，a3=$\frac{1}{4}$，则Sn的取值范围是[16，$\frac{128}{7}$）．