地理老师把一幅世界河流分布示意图挂在黑板上,问:“同学们,这幅示意图上的河流有什么特点?”“都不是直线,都是弯弯的曲线。”同学们回答说。“为什么会这样呢?河流为什么不走直路只走弯路呢?”老师继续问。同学们七嘴八舌地议论开来。有的说,河流走弯路,拉长了河流 Geography teacher put a schematic diagram of the distribution of the world’s rivers hanging on the blackboard, asked: “classmates, what are the characteristics of the river on this map? ” “Are not straight, are curved curve. Replied ”Why is this? Why do not the rivers go straight? Only the detours?" The teacher continued. Students talked about in rumors. Some say the river detours and lengthens the river