写法指导 说明文是以说明为主要表达方式的文体。它主要用来说明事物的特点、发展变化规律及分析前因后果，目的在于使读者获得必要的信息，使人们对事物有个清晰、完整的了解和认识。说明文分为三种类型：实体事物说明文，包括说明书、广告、解说词等；事理说明文，包括理论性概念解释、书文简介、教材

写法指导
　　说明文是以说明为主要表达方式的文体。它主要用来说明事物的特点、发展变化规律及分析前因后果，目的在于使读者获得必要的信息，使人们对事物有个清晰、完整的了解和认识。说明文分为三种类型：实体事物说明文，包括说明书、广告、解说词等；事理说明文，包括理论性概念解释、书文简介、教材等；文艺性说明文，即要把说明的对象拟人化，进而编成一个故事介绍给读者。
　　写说明文要注意以下几点：
　　1．要抓准特征。对某一事物予以说明，首先要弄清从哪些方面加以说明才能准确地反映被说明的事物。一般说来，说明事物可以从被说明事物的颜色、形状、形态；性质、性能、习性；原因、原理；作用、用途、功能；危害、影响；结构；操作过程；发生、发展的规律等方面着手。但是，每一事物都有它自己的特征，从而显示出了这一事物与其他事物的根本区别，因此，在说明事物时，不要面面俱到，要抓住事物的特征，这样才能使读者得到具体而深刻的印象。
　　2．层次要分明。说明事物要注意条理，否则就不可能说清复杂的事物。例如说明事物的结构，就要按照构造的顺序来说明，或从上到下，或从前到后，或由外到里，或由主到次。又如说明四季的变化，就要按照时间的顺序(spring, summer, autumn, winter)来写。
　　3．解析要清楚。对各种知识所作的解释，对某种事物所作的说明，都要清楚明白。
　　4.表现手法要多样。常见的说明文方法有：①下定义。②举例子。③运用比喻、比拟的方法。④做比较。⑤引用数字。⑥分类别。⑦列图表。
　　5.用词要力求准确。引用的数据要绝对可靠，文字要简明扼要，一目了然。这是写说明文在语言文字上的要求。
　　请看下面的例文：
　　
　　例文
　　Hello，friend,
　　You are warmly welcomed to our school. I'm Wu Dong.I'm very glad to be your guide. First, I'd like to tell you something about our school. It was set up in 1957. The number of students is over 1,200, and the number of the teachers is about 100. There are altogether 20 classes. Besides the teaching buildings, we have a library for different kinds of subjects, and a school-run workshop.
　　We have four classes in the morning and two in the afternoon. After classes, we join in various activities, such as ball games, painting, singing and dancing.
　　Now let me show you around our school. This way, please.
　　
　　名师点评
　　本文是一篇说明文，是由学生接待来访的朋友，向人们介绍本校的情况。本文目的明确，材料准确、翔实，语言简练，并能按一定的顺序来写，是一篇较好的说明文。
　　
　　佳作展示
　　My Pencil-box
　　I have a very beautiful pencil-box. I like it very much. One day six years ago when I was in the primary school, my mother took me to a shop to buy the pencil-box. I still remember that first I saw a big and beautiful one, but it was not strong enough. I didn't like it at all. Then we continued to look for another pencil-box. Suddenly I saw a very small but nice one, and it was also stronger than others. So I was very glad ① to buy it, on which ② we only spent five yuan.
　　I looked at the pencil-box carefully. There were two cats and some mice on it. The cats didn't want to eat the mice. They seemed to be very friendly. They even played together happily. How funny!
　　Since I had the pencil-box, I could put my articles (用品)for study such as rubber,ballpens, knife, ruler in it. When I was doing my lessons or homework ③, I could use some of them freely.Since then I wasn't afraid to lose them any longer. The box became my good friend. How good and convenient(方便) !