11. I'll call the police if you don't leave me alone.
⇒ Unless you leave me alone, I'll call the police.
12. Many people speak English in the world.
⇒ English is spoken by many people in the world.
13. People get more diseases. The water is contaminated.
⇒ If the water is contaminated, people will get more diseases.
14. David had gone home before we arrived.<CÂU NÀY ĐỀ SAI NHA BN>
⇒ After David had gone home, we arrived.
15. Aquatic life suffers or dies because there is thermal pollution.
⇒ Because of the thermal pollution, aquatic life suffers or dies.
16. You use compact light bulbs. You save a lot of energy.
⇒ If you use compact light bulbs, you will save a lot of energy.
17. They are going to organise a garden party to raise money for the victims of the flood.
⇒ A garden party is going to be organised to raise money for the victims of the flood.
18. The waiter took my plate. I didn't finish eating my meal yet.
⇒ The waiter had taken my plate before I finished eating my meal.
