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.

1.When did people talk about school buses?

A In 1939.

B In 1948.

C In 1949.

D In 1958.

解析：选A。A细节理解题。根据第一段中的“In 1939, a university professor (教授) met with teachers, engineers (工程师), and other experts (专家). They talked about school buses.”可知，1939年，一位大学教授会见了教师、工程师和其他专家，他们讨论如何使校车更安全。故选A。

2.______ say that the yellow color is the best.

A Professors

B Experts

C Teachers

D Engineers

解析：选B。B细节理解题。根据第二段第一句“Experts say that the yellow color is the best.”可知，专家说黄色是最好的。故选B。

3.What color are the letters on school buses?

A Yellow.

B Blue.

C Black.

D Red.

解析：选C。C细节理解题。根据第二段第二句的“You can easily see black letters on it.”可知，校车上写着黑色大字。故选C。

4.Does the bus color have its own name?

A No, it isn’t.

B Yes, it is.

C No, it doesn’t.

D Yes, it does.

解析：选D。D细节理解题。根据第三段最后一句的“The color even has its own name.”可知，校车的这种颜色甚至有自己的名称。故选D。

5.Where can we read the passage?

A On a stamp.

B In a school newspaper.

C In an English dictionary.

D In a world map.

解析：选B。B推理判断题。根据全文内容可知，本文主要描述了美国校车为什么是黄色，属于学校生活方面，我们可以在学校报纸上读到本文。故选B。