【听力原文】
By me end of the term，I hope you will be convinced as I am that formal writing always requires revision．Sometimes it requires a fairly major rewriting of the paper．Some students have the mistaken idea that revision means simply making corrections in spelling and grammar．I call that proofreading．[9]What I expect you to do with your revise is to evaluate and improve the overall effectiveness of your paper．But how can you tell if your paper is effective? Well，for example,start by asking yourself these questions：Is the topic restricted enough to be fully discussed within the given length? Are the main ideas clear? Are they supported by specific details and examples? Do they move smoothly from one idea to the next? You need enough time for a possible major overhaul． That is you may have to make a lot of changes before your paper becomes really clear to the reader. [11] So I'll expect a preliminary draft of each paper two weeks before the final due date. That way I can criticize it and get it back in time for you to revise it. Then you can submit a final draft for grading. This process may seem like a great deal of trouble at first, but I think you'll find it valuable. In fact, after you finish this course, I doubt that you will ever turn in a term paper without first revising it carefully.
What is the purpose of the talk?
【解题思路】
1．四项均为不定式短语，表示目的。
2．两项提到writing，考查内容可能与写作有关。
结论：本题应该是考查目的，内容可能与写作有关。
【解析】本题考查听力短文的主旨。开头处说话人希望学生相信正式写作是需要校正、修改的，有些学生错误地认为修改就是简单地修改拼写和语法方面的错误，但说话人要求的修改是评估并改进文章整体的效果。后面说话人又介绍了如何修改文章，因此说话人的目的是想改变学生的写作方式，故答案为B。