How To Use FOR in English, Definition and Example Sentences We use FOR to talk about a length of time, a period of time. Example Sentences; I have worked here for 8 years. You have played football for ten years. We have taught at this school for a long time. He has been a student for eight years. They’ve been married for 30 years. She has been in prison for 6 months. I haven’t been on holiday for ages.