Oil

Nowadays, we worry about oil costs because oil has been exhausted. I think that after 40~50 years, oil will be gone because people are using it a lot. And, oil price is going to increase more and more. So, many people will use decreasing amount of oil. Moreover, the world will try to make alternative energy. Also, the biggest differences will be changing of fuel. Oil is going to disappear in the world. So, the world will change to cars such as hydrogen vehicles, natural gas vehicles, solar energy vehicles, etc. People will use alternative energy in the future.