题目

如图为△ABC与△DEC重叠的情形，其中E在BC上，AC交DE于F点，且AB∥DE．若△ABC与△DEC的面积相等，且EF＝2，AB＝3，则DF的长等于_________．   答案：2.5 There are _______ in the reading room, but many of those books aren’t _______ to read. A. enough books, enough easy                 B. enough books, easy enough C. books enough, easy enough                 D. books enough, enough easy