một đoàn xe gồm 2 loại, loại thứ 1 gồm 4 chổ ngồi, loại thứ 2 gồm 32 chổ ngồi, đoàn xe chở 328 vừa đủ. Bt loại xe thứ 1 nhiều hơn loại xe thứ 2 là 1 xe. Tìm số xe của mỗi loại.

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VI Fill in the blank with the correct form of the given word. 1. Many people don’t know about the ………………. of soil pollution. dangerous 2. The river is seriously ……………….by the factory’s waste. contaminate 3. High blood ……………….can be brought about by noise pollution. press 4. The water color can show us how ……………….the river is. pollute 5. A lot of ……………….fish are floating on the surface of the lake. die C. READING VII Read the passage. There are three main (1) ……………… of pollution: air pollution, water pollution and noise pollution. Air, which is the most important element of our environment for our (2) ……………………, can be polluted in many ways. Smoke in the air from mills, factories and industry (3) …………………… carbon, monoxide, carbon dioxide, and methane, which are all poisonous gases. This leads (4) …………………… health problems like asthma and lung diseases, and the thinning of the ozone layer, which (5) …………………… us from harmful UV ray. China, the USA, Russia, India, Mexico and Japan are the world leaders in air pollution (6) …………………… Water is also polluted by the discharge of commercial and industrial waste. Sewage in drinking water is another (7) …………………… of water pollution as it contains germs and viruses. The noise of vehicles, mills, and factories can be really unbearable. This kind of constant sound also (8) ……………… headaches, tension, (9) ……..………… stress and migraines. People living next to a building site where there is too much noise can become sick, as they can not sleep or relax. This is (10) …………………… noise pollution. Choose the best answer (A, B, C or D). 1. A. types B. kinds C. models D. both A & B 2. A. survival B. survive C. surviving D. survived 3. A. includes B. include C. contains D. contain 4. A. in B. into C. to D. from 5. A. prevents B. protects C. avoids D. hides 6. A. emissions B. emitted C. emission D. emitting 7. A. effect B. cause C. result D. consequence 8. A. causes B. leads to C. results in D. all are correct 9. A. brain B. mind C. head D. mental 10. A. told B. called C. said D. mentioned Answer the questions below. 1. What are the examples of health problems caused by air pollution? 2. Why is sewage in drinking water another cause of water pollution? 3. What does the writer says about the noise of vehicles, mills and factories? VIII Read the passage. Answer the questions below. Scientists have discovered that the ozone layer is getting thinner. Some predict that the sun’s rays will cause a sharp increase in deaths from skin cancer over the next fifty years. These harmful rays can also damage the eyes, create wrinkles, and cause other health problems. The stratosphere contains a form of oxygen called ozone. Ozone is a molecule composed of three oxygen atoms. The chemical formula of ozone is 03. Oxygen molecules make up about 21% of all gases in the Earth’s atmosphere. They consist of two atoms of oxygen and are labeled 02. Most ozone found in our atmosphere is formed by an interaction between oxygen molecules and ultraviolet radiation (UV) from the sun. When ultraviolet radiation hits an oxygen molecule, it may cause the molecule to break apart into single atoms of oxygen. These single atoms are very reactive, and a single oxygen atom can combine with a molecule of oxygen to form ozone. 1. What do people say about the rate of deaths from skin cancer in the future? 2. How many oxygen atoms are there in a molecule? 3. What elements participate in the formation process of ozone? 4. What happens when an oxygen molecule and an ultraviolet radiation hit each other?