: I. Choose the best answer:

1. If the factory (continues/ to continue/ continued) dumping poison into the lake, all the fish and other aquatic animals will die.

2. Water (pollution/ pollute/ polluted) in the lake has made the fish die.

3. Mi and Nick like (comes/ come/ coming) back Mi’s home village on holiday.

4. If the factory continues dumping poison into the lake, all the fish and other aquatic animals (will die/ to die/ dead)

5.Water pollution is the (contaminating/ contaminate/ contamination) in the lake has made the fish die.

6. If we (will use/ would use/ use) water carefully, more people will have fresh water.

7. If the factory continues dumping poison (into/ to/ about) the lake, all the fish and other aquatic animals will

die.

8. Farmers in our area usually use (pesticides/ herbicides/ waste/ sewage) to kill insects

9. If we (polluted/ pollute/ pollution/ pollutant) the air, more people will have breathing problems

10. If you can experience noise pollution for a long time, you can have headache, high blood pressure and (hearing loss/ contaminant/cough/ radiation)

11. Because the water is polluted, (aquatic/ electric/ chemical/ fresh) plants may also die

12. (Noise/ Headache/ Earplug/ Symptom) is any sound that is loud and constant.

13. Do you know what (polluted/ pollute/ pollution/ pollutant) cause air pollution

14. (Poison/ Poisonous/ Poisoning/ Poisoned) chemical waste is dumped into the river by many factories

15. The (dead/ die/ death/ died) fish are floating in the water.

16. We plant trees, (due to/ because/ because of/ so) we can have fresh air.

17. When the loudness of sounds is more than (20 dBs/ 30dBs/ 50 dBs/ 70dBs), noise pollution happens

18. Too much carbon dioxide (CO2) in the atmosphere (causes/ lead/ result/ make) to global warming

19. Waste from households will gradually (contamination/contaminate/contaminant/ contaminated) the lake.

20. When (visual/ thermal/ light/ radioactive) pollution happens, the water temperature in streams, rivers or oceans changes.

21.We can’t see stars at night (because of/ because/ since/ due) the light pollution.

22.If you (was / were/ are/ could be) in my position, you would understand me.

23.When (visual/ thermal/ light/ radioactive) pollution happens, the water temperature in streams, rivers or oceans changes.

24.Many seabirds were (die/ death/ dead/ died) because of the oil spill.

25.(Aquatic/ Electric/ Chemical/ Fresh) plants may also die because of the polluted water

26. Many animals eat the (litter/ energy/ aqua/ temperature) and become sick.

27. The acid rain has caused (damage/ advantage/ pollutant/ environment) to the trees in this area.

28.If I (have/ has/ had/ will have) one million US dollars , I would build more parks in our city.

Cho nửa đường tròn (O) đường kính AB = 3cm. Trên đường tròn (O) lấy điểm C sao cho \(\widehat{ABC}\) = 60⁰, kẻ tiếp tuyến Cx với đường tròn (O). Qua (O) kẻ đường thẳng d song song với BC. Gọi D là giao điểm của d và Cx.

a) Cmr: DA là tiếp tuyến của đường tròn (O).

b) Cmr: Tam giác ACD là tam giác đều.

c) Tính diện tích tứ giác ABCD.

Tính giá trị biểu thức:

\(5.\tan40^0.\tan50^0-\cos^247^0-3-\cos^243^0\)