说明文用来解释或说明理论，方法，过程或某种抽象的情况。这里所说的说明文主要是"
按图表写作文，首先要读懂图表，理解其包含的信息。为此目的，应注意三点：第一是读懂标题，明白图表的目的;第二是研究图表主题，理解各项内容及其之间的联系;第三是注意图表的说明或图例，以免误解。总之，对图表的研究要仔细,理解和判断要准确，不能草率做出决定，以免在文章内容方面丢分。
读懂图表之后，立即思考文章应表达的内容。这里,我们应该明白两个制约因素：其一是作文写作时间只有二十多分钟，不可能长篇大论;其二是图表内容繁多，不可能一一说明，也不能写成枯燥无味的流水账。考虑取舍时,应注意总的趋势，概貌，相互关系，典型的例子或数据，抓住这些之后，其他的内容实际上也包含在其中，不必再提及。
文章的写法没有固定的模式，但因题材的限制，变化太大也不可能。第一段必须说明图表的性质与目的，没有这一点，文章的主题难以突出。自然段的划分以清楚明了为原则，例如第一段谈图表的目的，其余自然段应当以所谈要点划分，最后一段可谈自己的理解和看法(也可不谈)。写作时的关键是每个要点谈完后,应给出例证，把该说地说完,然后再进入下一要点，不能不顾文章条理,把想到的内容随便乱放。
再语言方式上，要注意句式的变化，尽量避免反复使用某一句型。再并列情况较多时，设法采用连结词或关系词将领岁的内容串在一起，为文章的主题服务。全文的思路可以用主题句，自然段,逻辑词等手法表明，使读者感到作者的思路清晰，感到全文是个有机的整体。遇到众多雷同的词汇短语时，能变化的尽量变化，无力变化时可用句式变化弥补。TOEFL范文
If your friend fails to return your money in time, how could you do to get it back and to ask him to return your money in person or by writing a letter? Use specific example.
Undoubtedly, everyone has one or more friends in his or her daily life. Someone often comes across the fact that one of his friends borrows some money from him but doesn't return it in time. At this time, he must be confronted with the question how he could do to ask his friend to return his money in person or by writing a letter? If I were forced to choose one of the two, I prefer to ask him to return my money by writing a letter.
One sound reason why I choose writing a letter is based on one true story. Last month, I received a letter from one of my friends unexpectedly. The letter says: " Hello, my dear friend, it's a long time since I saw you last time. I am sorry to bother you when you are up to neck in work, but would you think about the fact that you still haven't returned my money in time? For some reason, I need to use it. Could you return my money back? Thanks for your consideration." I didn't remember the thing until the letter astonished me. Certainly, a few days later, I returned my friend the money and gave him my regret. In my opinion, the letter doesn't hurt me. It helps me to get along with my friend more closely and intimately. If I hadn't received his letter, it would have ruined our friendship in a silent ripple only because of some money. The story is not rare. It can easily come to the conclusion than it is better to get money back by writing a letter.
Although somebody prefers to get his money by asking his friend to return his money in person, I think the notion is negative. As far as I am concerned, Everyone suffers from the strain of modern life. If you drop by your friend just because you want to get your money back ,it will hurt your friend and obviously hurt your relationship. However, a courteous and kind letter not only can solve the problem that wraps you, but also can have your relationship further develop.