だらだら課題

Today, energy source which we use mainly around the world is oil. The machine which is around us , for example there are the car, ship, air plain and motor bike, mostly uses the oil. So I think that the oil plays an important role of the current society. Recently electrical machine is produced by company and, in fact, we come to use it. But I think main energy is the oil because transportation organization of using the electricity mainly is only train.