题目

 The firemen managed to _____ the fire in time. A. extinguish       B. prevent      C. suppress     D. ruin 答案：【解析】A. extinguish (=put out) vt. 扑灭 (火焰等) 。Stop the fire虽然也可以搭配, 但按本句题意用extinguish为最佳。已知数列{an}的前n项和为Sn，对任意n∈N*，都有，且ak=8，则k的值为A.1 B.2C.3 D.4