六下 Unit4 Road safety 单元知识一、词组:1. road safety 道路安全2. many busy roads 许多繁忙的道路3.in the city在城市里4. cross the road safely 安全地过马路5. cross a busy road safely安全地通过一条繁忙的马路6. look at the traffic lights 看交通灯7. wait for the green man 等待绿灯8. see the red man 看红灯9. keep safe 保持安全10. wait on the pavement 在人行道上等待11. look out for cars and bikes 小心小汽车和自行车12. look left看左边13. look right 看右边14. cross the road with other people和其他人一起过马路15. see you easil