阅读下面流沙河的《就是那一只蟋蟀》中的片段完成下列问题。
                                                                                   就是那一只蟋蟀
                                                                                   就是那一只蟋蟀
                                                                                   在海峡那边唱歌
                                                                                   在海峡这边唱歌
                                                                                   在台北的一条巷子里唱歌
                                                                                   在四川的一个乡村里唱歌
                                                                                   在每个中国人所到之处
                                                                                   处处唱歌
                                                                                   比最单调的乐曲更单调
                                                                                   比最和谐的音响更谐和
                                                                                   凝成水
                                                                                   是露珠
                                                                                   燃成光
                                                                                   是萤火
                                                                                   变成鸟
                                                                                   是鹧鸪
                                                                                   啼叫在乡愁者的心窝
                                                                                   就是那一只蟋蟀
                                                                                   在你的窗外唱歌
                                                                                   在我的窗外唱歌
                                                                                   你的倾听
                                                                                   你的想念
                                                                                   我在倾听
                                                                                   我在吟哦
                                                                                   你该猜到我在吟些什么
                                                                                   我会猜到你在想些什么
                                                                                   中国人有中国人的心态
                                                                                   中国人有中国人的耳朵

下列说法中正确的是（   ）

如图，在△ABC中，DE∥BC，DE与边AB相交于点D，与边AC相交于点E，如果AD=3，BD=4，AE=2，那么AC=____．

已知一个几何的三视图如图所示，图中小正方形的边长为1，则该几何体的体积为（  ）