A school bus is one that is used to take children to and from school. In the USA, about 45

A school bus is one that is used to take children to and from school.
In the USA, about 450,000 school buses take more than 25 million children to and from school. The yellow school bus is a US icon (象征). Yellow became the color of school buses in the USA in 1939. Dr. Frank got the good idea. He said it was easy for people to see yellow buses and the black letters on them in early morning or late afternoon. That would make children safer.
There are not many school buses in Britain, and they are not yellow. They have trackers (追踪器) on them, so kids are being tracked while they travel to and from school by bus. The trackers let parents know where the school bus is and whether their kids are on the bus.
Kindergarten (幼儿园) is a difficult time for some kids. It's the first time for them to go away from their parents. To make kids love their school, Japanese kindergartens and schools have colorful buses. The buses can easily make children want to take them--and then, go to school. Even some parents want to take them, too!
School buses are becoming more and more popular in China now. It saves a lot of time for students to take a school bus. It's said that there will be 3,000 yellow school buses on the road by the end of this year in Chongqing.
【小题1】According to Dr. Frank, school buses are safer for the students.A．yellowB．blackC．whiteD．colorful【小题2】Children in Japan may easily by taking the school bus.A．save timeB．love their schoolC．play gamesD．do their homework【小题3】Chinese students will save a lot of time to to school.A．walkB．take a taxiC．ride a bikeD．take a school bus【小题4】This passage is mainly about .A．school busesB．school lifeC．popular colorsD．students' safetyA

(答案→)A 解析：本短文属于说明文。对几种典型校车做了介绍。【小题1】第二段，有答案。【小题2】从第四段，第三句中，可知。【小题3】最后一段的第二句，可知。【小题4】文章第一段谈校车的作用，接着谈美国校车的颜色、英语校车的trackers，日本校车的彩色，中国校车的发展。整篇文章都在围绕校车这一主题展开。

我明天再问问老师，叫他解释下这个问题