出国留学网英语栏目为您推荐“双语资讯之交通信号灯为什么是红黄绿三种颜色”，希望能帮助到您! Red means "stop," green means "go," and yellow means "hurry up and make that damn light." Why those colors, though? Why not blue, purple, and brown? I have to admit that aside from a hunch that it had to...