阅读短文，选择正确答案。

Vivian is a girl. She is a good student. She likes reading and writing. She goes to the library every week. Usually, she goes by bike. Sometimes she goes on foot because the library is not far from her home. She always pays attention（注意，留心） to the traffic lights(交通灯). They are the same in other countries. Red means "Stop and wait." Yellow means "Slow down and stop." Green means "Go." But some traffic rules are not the same in different countries. For example, in the UK, people drive on the left side. In China, people drive on the right side.