I want to talk about the purpose. As everyone know, purpose is really important for a research essay, because you need to get a clear purpose for your essay before you begin writing. And purpose is useful to help you to find some information or useful essay. First, I want to talk about how to know a writer's purpose.  

As this form, purpose is the reason for communication, and you can think it is the reason why this writer want to finish this essay. These two example from my reading, and they are two writer' thinking about purpose. These thinkings are same as me. We all believe purpose is important for writing. If you want to know a writer's purpose, you need to find some main idea sentences. They can show you the writer's purpose really clear, because key sentences always include the main idea for an essay. When you know the main idea of an essay, you can find the purpose of this essay really easy. So, going to find some key sentences when you want to know the writer's purpose. 

Next,  I want to talk about how to use the purpose. When you know how to find a writer's purpose, you can use this skill to help you to find some helpful information. When you want to find some essay to support you essay, you will get a lot of essay that you can choose. How to know which is helpful to you? Purpose! You can use writer's purpose to find. If the writer's purpose is similar as your purpose or it has a link between your purpose and this writer's purpose, maybe this essay is useful to you.

Finally, I will show an example from my experience about my research essay. My purpose is research about 'Should there be a course for students of this type of major on how to describe their ideas to non-professionals'. I choose this topic because I met a lot of trouble about this problem. I find an essay from Robyn Woodward-Kron named 'More than just jargon--the nature and role of specialist language in learning disciplinary knowledge'. The purpose of this essay is confirming the importance of technical terms. It have some links for my purpose, because I need to confirm the importance of technical terms, too. It can help me to confirm this kind of class is helpful for students from some special major who meet the same trouble with me. So, I think this essay is useful for me, because it can support my purpose. I think use this way to find some useful essay and informations is really good.