when like falling used more cuts air study so save much how |
Nowadays more and more people care about the exploitation (开采) of the natural resources, such as oil. The_______ oil we use, the less these will be left for the future. Oil can be ___
____in many ways and it’s difficult to imagine what the modern world will be _
____ without oil. But oil isn’t easy to find and get out of the earth. Men must __
_____ the rocks, ___
____they think the rocks in a certain place may have oil, a metal tower is built. A machine in the tower __
____ a hole down into the ground. At the same time , a steel pipe (钢管) is pushed down to stop the sides from __
____ in and to keep out water. At last if the men are right, usually the oil rushes up high into the __
___. If the oil catches a light , there will be a terrible fire, __
____a kind of cover is fixed on the top of the pipe. And the oil can run out through taps( 活塞). Today the price of oil keeps rising all the time. In many countries, the governments encourage people to _
___oil as much as possible.