make choices that allow you to achieve your purpose with that audience. If you're selling computers, you need to know when to use computer jargon and when not to, for example. If you want to get permission to do something on a job, you need to know if your boss prefers a quick request in person or a detailed written analysis to look over. Then you provide whichever is going to work with that audience. In school, the teacher is usually your audience. The objectives are what the teacher wants you to learn. Your purpose is to show the teacher that you've achieved those objectives so that the teacher will give you a good grade. ]