陕西 张辉 陈云
说明文主要用来对客观事物和主观思想进行介绍、解释和阐述。写好说明文可以从以下几个方面入手：
常用时态、语态：一般现在时，被动语态。
常用人称：第二、三人称。
语言效果：
1. 语言要力求给人以客观、真实可信的感觉。一般不用第一人称以避免主观色彩，若用被动语态则表达效果更佳。
I think that getting up late is not always a bad thing.
→It is said that getting up late is not always a bad thing. （被动）
2. 引用名人名言作为信息的来源可使内容更具有说服力；另外要避免使用语气过强的词汇。
Getting up late is not always a bad thing.
→Getting up late is not necessarily a bad thing, according to Franklin Smith, a well-known psychologist in Stanford University.
文章结构：
第一部分：提出文章的主题，即文章想要阐述、说明的主要内容。常用表达方法：As we can see …；As we all know …：Do you know…等。
第二部分：文章的主体，可由若干个段落组成，对文章的主题进行展开说明。
第三部分：结尾段，对文章的主题作归纳总结。常用表达方法：This is (so called)…；From the above, we can see…等。
写作练习：
请根据以下信息并结合相关学科知识，用英语写一篇关于水循环的科普短文，词数100~120左右。
Lake/ river →sea →ocean → evaporate（蒸发）→clouds→condense（凝缩）→rain→lake/river
One possible version:
The Water Cycle
As we all know, more than 70% of the surface of our globe is covered by water. Do you know where the water comes from and why the water doesn’t dry up? This is because of the water cycle.
First, when the weather is fine, the heat of the sun evaporates water from the rivers, lakes, seas and oceans. Thus water vapor is formed, which rises and forms clouds in the air. And then, when the clouds rise, they are cooled. The higher they rise, the cooler they are. This causes more and more water vapor to condense. In this way, the tiny drops of water in the clouds get bigger and bigger until they are heavy enough to fall to the earth as rain.
Some of the rainwater sinks into the ground, and is used up by plants. Most of them goes back to the rivers, lakes, seas and oceans.
This is called the water cycle, which starts all over again.
来源:互联网
