题目

It’s hard for people to make their way ________. A. in the rushing hours       B. at the rushing hours C. at the rush hours           D. on the rush hours   答案：C 已知函数的部分图像如图所示，则f(1)＋f(2)＋…＋f(2007)＋f(2008)＝＝________．