時序式寫作就是依照時間順序來寫文章。

時序可以出現一個單獨的段落，或是整篇文章就是依照時序來鋪陳。

 

請先閱讀一下以下範例文章

Let us briefly review the recent history of fuel economy in American automobiles. In 1974 the average car sold in the US achieved an on-the-road fuel economy of a little more than 13 miles per gallon of gasoline. By 1980 the figure had risen to an estimated 19 m.p.g. By mandate of Congress, the fleet of automobiles built for the 1985 model year must achieve an average of 27.5 m p.g. as measured by dynamometer tests administered by the Environmental Protection Agency (EPA). This figure was set by Congress at almost exactly double the fuel economy of the 1974 model year (as determined by the same testing method). The Department of Transportation was also instructed to set fuel-economy standards for light trucks at the "maximum feasible level." Recently the department determined that, in view of the current financial problems of the indusry, it could set this level no higher than 21 m.p.g. in 1985.
"The Fuel Economy of Light Vehicles, " Charles L. Gray, Jr and Frank von Hippel, Scientific American (April 1981)

 

解析：開場白就立刻使用兩個介系詞片語 (preposition)，In 1974 以及 By 1980，然後接著第二句與第三句，讓讀者可以很快感受到時序發展的邏輯。

思考：

1. 文中的 This 指的是什麼？

2. 文中的縮寫 m.p.g. 指的是什麼？

3. 在段落的前兩句有重複出現，用來幫助 coherence 的文字是什麼？

4. 在段落的最後兩句有重複出現，用來幫助 coherence 的文字是什麼？

5. Topic sentence 中哪一個字最能表示整段的 Controlling idea?

 

科學寫作很常使用時序式的段落，尤其是在描述方法的時候。這是最自然的寫法。

讓我們看看下方的例子：

 

To build your own sunscope, get a carton and cut a hole in one side big enough to poke your head through. Paste white paper on the inside surface that you will be facing. Then punch a pinhole into the opposite side high enough so that the little shaft of light will miss your head, For a sharper image you can make a better pinhole by cutting a one-inch square hole in the carton, taping a plece of aluminum foil over this hole, and then making tho pinhole in the foll. Finally, tape the box shut and cover all light leaks with black tape.
摘錄自 "Building a Sunscope." Life (July 12, 1963)

 

解析：整個段落就是一步一步教你如何製作 Sunscope，其中使用 then 以及 finally 兩個連接詞，幫助增加段落的 coherence。這可以說是最典型的時序式寫法。

 

另外，有時候一個段落裡會同時有幾個時序的內容。這種寫法在許多教科書中都會出現，例如下面的範例：

One of the most widespread uses of the electromagnetic principle is in relays. These are nothing more than magnetically operated switches. Such switches could have one contact (single pole) or many contacts (double pole, triple pole, etc.) The contacts could be normally open are closed by electromagnetic action, or, vice versa, the contacts cold be normally closed and are opened by electromagnetic action. An example of this second type is the circuit breaker used to protect against overloads or short circuits. The circuit breaker is closed manually to apply power. Should the current in the circuit at any time exceed some preset limit, the electromagnetic action of the relay will cause the circuit breaker contacts to open. Another example of the normally closed relay is the reverse-current relay used in the battery-charging circuits of aircraft and automobiles. When the engine is running at above some minimum speed, the generator charges the battery. If the engine is stopped (or running at too low a speed), the generator cannot supplly power to the battery, but the battery could discharge-or even be short-circuited-through the generator. A reverse-current relay will open the circuit between generator and battery and prevent discharge of the battery. This simple electromagnetic device is a major factor in our automated technology. In the home, relays are responsible for the clicks and clacks heard during operation of dishwashers, clothes washers, air conditioners, etc. In industry, relays are the "fingers" that control the sequence of operation in the myriad of automated processes.

摘自 "Relays," J J. Defrance, Electrical Fundamentals

 

解析：

1. 上面的文章來自電磁學教科書。作者很清楚即使是理科學生，電磁學的內容仍然是蠻難讀的。所以在段落中作者大量使用 transitions，儘量使用短句，在字彙上也選擇比較簡單直接的。

2. 前四句，利用重複出現的的代名詞 (標紅字) 建立的邏輯的線性，這是一種可學習的寫作方式

3. 隨著段落發展，兩個 Transition (標藍字) 扮演了重要的角色

4. 在結尾的時候，使用平行法 (標紫字)，來釐清段落的兩個概念

5. 中間使用 "Shold" 來表示有條件的可能 (conditional probability)