彩虹为什么是半圆的？

A rainbow looks like a half circle. 彩虹看着呀，像半个大圆圈。 But the whole rainbow is a full circle. 其实彩虹，是一整个完整的圆。 The ground blocks the lower half. 地面挡住了下面那一半。 From a plane, you can see the whole ring. 从飞机上往下看，能看到整圈。 Rain drops split sunlight into colors. 小雨滴把阳光，拆成了好几种颜色。 Red stays outside, and purple stays inside. 红的在最外面，紫的挨着里面。 A rainbow is always an arc around you. 彩虹呀，永远绕着你画弧。