Dưới đây là các từ mà bạn cần điền theo gợi ý:

1. **Public transport**: buses and trains that people pay to travel on
2. **Traffic jam**: a long line of vehicles waiting to move
3. **Crowd**: large numbers of people in one place
4. **Graffiti**: words or pictures that we see on walls
5. **Rush hour**: the busiest period in a city for traffic
6. **Green spaces**: areas of grass and trees in a city
7. **Litter**: things some people don't want and leave on the street
8. **Blackout**: when an electrical system stops working