Unit 1:by (经,乘) foot(脚) bike(自行车) bus(公共汽车) train(火车) how(怎样) go to school(上学) traffic(交通) traffic light(交通灯) traffic rule(交通规则) stop(停,停车站)wait(等待) get to(到达) Unit 2
problem, some pieces of advice are put forward. Some people suggest that more streets and roads should be built. Some people advise to limit the number of bikes and cars. This can decrease the traffic flo