奇速英语

There are 480,000 school buses in the US. They take children to school every day. Most of them are yellow. In 1939, a university professor (教授) met with teachers, engineers (工程师), and other experts (专家). They talked about school buses. They wanted to make them safer (安全的).

Experts say that the yellow color is the best. You can easily see black letters on it. When the weather is bad, people can see yellow easily.

No US law says that school buses must be yellow. Many people say that yellow is the safest color. Now, most buses are yellow. The color even has its own name.