Nowadays more and more people care about the exploitation of the natural _ , such as oil. Though there're many kinds of resources, with the fast increase of population and the increase of many more factories, the more we use, the fewer there will be left for the future. Oil is getting less and less year after year. It's said that oil can last for only 50 years. Natural gas perhaps will last about 38 years. Oil can be used in many ways and it's difficult to imagine what the modern world will be like without oil. But oil isn't easy to find and get out of the earth. Men must study the rocks. When they think the rocks in a certain place may have oil, a metal tower is built. A machine in the tower cuts a hole down into the ground. At the same time, a steel pipe is pushed down to stop the sides from falling in and to keep out water. At last if the men are right, usually the oil rushes up the sides with great force by the pressure of the gas in the top of the rock, and it rushes high into the air. If the oil catches a light, there will be a terrible fire. So a kind of cover is fixed on the top of the pipe, and the oil can run out through taps . If we are near the middle of the oil field, we can also get gas. Such gas is sent through pipes to towns far away and used in houses and factories like coal gas. Today oil is under pressure as never before. The price of oil keeps rising all the time. In many countries, the governments encourage people to save oil as much as possible. Which of the following can be true according to  the passage?
Coal gas can't be used in houses and factories. Oil is very important in the modern world. Many governments encourage people to waste oil as much as possible. It's very easy to get the oil.