A、One. B、Two. C、Three. D、Four. C文中说：五段式论文的基本结构是：首先，写一篇介绍性段落来说明论点。然后，添加三个举证段落。最后，写一段结论。

Millions of students have been taught a formula that has nothing to do with chemistry. The formula is for how to write a five-paragraph essay. First, write an introductory paragraph to state the argument. Then, add three paragraphs of evidence. Finally, write a conclusion.
    Linda Bergmann is director of the Writing Lab at Purdue University in Indiana. Her job is to help students, including international students, improve their writing. Professor Bergmann has worked with many students who learned this traditional five-paragraph formula.
    Professor Bergmann says international students sometimes have difficulty with this formula if they learned a different writing structure. But just knowing how to write a five-paragraph essay is not going to be enough for a college student who has to write a longer academic paper. The formula is too simple to deal with subjects that require deeper thought and investigation.
    So what are the qualities that make up good writing? Karen Gocsi, executive director of courses in the Institute for Writing and Rhetoric at Dartmouth College in New Hampshire, says there are no simple answers — except maybe for one. That is, there is no formula that students can follow to guarantee a well-written paper. As she points out, "The thinking that you are doing, and the purpose that you have and the audience you are writing to — all of these things you will mix up together and you will come up with an excellent college paper."
    In some cultures, students organize their paragraphs to build toward the main idea at the end of the paper. American college students are usually expected to state their thesis at the beginning. And, while students in some cultures use lots of descriptive words, American professors generally want shorter sentences.
Q10: How many paragraphs of evidence should be included in the five-paragraph formula?
Q11: Why do international students sometimes have difficulty with the five-paragraph formula?
Q12: Which is NOT a typical essay structure in American college writing format?