Vocabulary

1. to obtain, buy, or earn something
2. to fall or to allow something to fall
3. the surface of the earth that is not covered by water
5. something that is of low quality
6. a sound or sounds, especially when it is unwanted, unpleasant, or loud
7. damage caused to water, air, etc. by harmful substances or waste
8. an empty area that is available to be used
9. to look somewhere carefully in order to find something
11. the number of vehicles moving along roads, or the amount of aircraft, trains, or ships moving along a route
15. to start to be seen or to be present
17. a very hard building material made by mixing together cement, sand, small stones, and water

1. words or drawings, especially humorous, rude, or political, on walls, doors, etc. in public places
2. to be in a place where no one knows
4. to find information, a place, or an object, especially for the first time
8. the grey, black, or white mixture of gas and very small pieces of carbon
10. to go away from someone or something, for a short time or permanently
12. the mixture of gases that surrounds the earth and that we breathe
13. off If the amount, rate, or quality of something falls off, it becomes smaller or lower
14. to be in a particular place
16. to come or go back to a previous place