Earth Hour happens on the last Saturday of March. Millions of people turn off their lights at 20:30 for one hour.Electrucity is very important.It can turn convenient in our live.When we switch on the air conditioner,we should close the doors and windows.When you leave the room,you should turn off the lights.When you are sleeping,you should switch off electrical appliances.When your hands was wet,you shouldn't touch any electricity appliances. When you switch off before bulb you should turn off electricity.So we should save the electricity in the earth.