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．yellow B．black C．white D．colorful 小题2:Children in Japan may easily by taking the school bus. A．save time B．love their school C．play games D．do their homework 小题3:Chinese students will save a lot of time to to school. A．walk B．take a taxi C．ride a bike D．take a school bus 小题4:This passage is mainly about . A．school buses B．school life C．popular colors D．students' safety