Energy is one of the problems that many people are interested in. It's not an unfamiliar word. It's heard, said, discussed day after day. It's close to everyone's daily life. First, we should turn off the lights before going to bed. Secondly, we should use low energy light bulbs. Thirdly, we should take a shower instead of a bath to save water. In conclusion, we need to turn off the light when we don't use it to save energy.