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.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?