英語說明文的寫作方法
1.定義法（definition）
定義法也是英語說明文中常用的寫作手法，特別是在對具體事物概念進行說明時經常使用。定義法的基本要素是定義句。英語中常見定義句的模式是：
被定義對象is所屬類別+限制性定語
可以看出，定義句中限制性定語越詳細，定義就越精確，比如：
A bat is a small mouse-like animal that flies at night and feeds on（以……爲食品）fruit and insects but is not a bird.
其實，在英—英詞典中，對英語單詞的英文解釋就是定義法的典型例子。比如，看看Longman詞典對student和teacher的定義是很有意思的：A student is a person who is studying at a place of education or training. A teacher is a person who gives knowledge or skill to sb. as a profession（專業）。
2.順序法（sequence of time，space and process）
順序法是指按時間、空間或過程的順序進行說明的一種寫作手法。比如按照時間順序介紹一個科學家的生平，用空間順序闡述逐漸開發西部的重要意義，用過程順序法解釋葡萄酒的生產過程等等。
下面這篇學生作文就是用順序法寫成的：
Coal
Coal underwent（經受）many changes before it became the bright，brittle（脆的），black substance which we now use. During ancient times（在上古時代），when the earth enjoyed a very warm and wet climate，the land was covered with large forests and big plants. As time went on，the ground changed and began to sink（下沉）a little. These very large numbers of trees and vegetables received a deposit（沉澱）of sand and clay. This layer of sand and clay pressed upon the layer beneath and prevented it from contact with air. These trees and plants received the pres sure and changed its appearance.
Generations after generations（幾世紀後），as the ground kept gradually sinking，another layer of sand and clay was again deposited（積聚）above the layers already formed. A great pressure was thus exerted（作用）and the peat（泥煤）was changed into the black and brittle substance which is known as coal.
Coal is a kind of mineral which is formed by nature as above stated. It is an important industrial material and is chiefly used as fuel. It is very valuable in the industrial world. The place where coal deposit is called a coal mine（煤礦）。 In China，coal mines are largely found in the north-west part of the country. Shanxi is a famous province for producing coal. It has the most coal of China.
3.分類法（classification）
分類法是將寫作對象進行分類說明的一種寫作手法。比如：著名的英國哲學家弗朗西斯·培根（Francis Bacon）在其膾炙人口的《談讀書》（Of Studies）一文中就用到了分類法：
Some books are to be tasted，others to be swallowed，and some few to be chewed and digested，that is，some books are to be read only in parts，others to be read，but not curiously，and some few to be read wholly，and with diligence and attention. Some books also may be read by deputy，and extracts made of them by others； but that would be only in the less important arguments，and the meaner sort of books…
參考譯文：書有可淺嘗者，有可吞食者，少數則須咀嚼消化。換言之，有隻須讀其部分者，有隻須大體涉獵者，少數則須全讀，讀時須全神貫注，孜孜不倦。書亦可請人代讀，取其所需摘要，但只限題材較次或價值不高者……
——轉摘自《英漢翻譯教程》（張培基等）
可見，如果能夠根據具體情況，選用合適的寫作手法，就可爲文章增添無窮的魅力。
除了上述提到的6種展開英語說明文主題的寫作方法之外，還有因果法、歸納法等其他方法。但相比之下，對於中學生來說，上述6種方法是首先值得掌握的。另外必須指出的是：在一篇文章中往往是以一種寫作手法爲主，同時輔以其他寫作手法。有時，甚至會幾種寫作手法混用而不分主次。因此，必須根據具體情況，選用合適的展開主題的寫作手法，才能寫出優秀的英語說明文。
