(5)比較和對比 比較(comparison)主要是指出兩個或兩個以上不同種類的事物的共同點或相似之處，如人物、地點、事物、思想、觀點等。對照(contrast)主要是指出它們的不同點。相同的或類似的特征可以組成比較，不同的特征則可以組成對照。不僅如此，比較和對比常常同時使用，這是因為比較中往往隱含著對比。
比較和對比常有兩種形式，即整體比較和對比(block comparison and contrast)與逐項比較(alternating comparison)，例如：
Although Ulysses S. Grant and Robert E. Lee were fierce adversaries during the Civil War, their lives, both military and nonmilitary, has a great deal in common. Grant descended from a family whose members participated in the American Revolution. He received his commission of second lieutenant from West Point and served in the Spanish-American War. He was later summoned by President Lincoln to assume command of the Union Forces during the Civil War. After the Civil War, Grant suffered financial problems and was forced to declare bankruptcy. Lee also descended from a family which engaged in the American Revolution. He, too, received his commission from West Point and later fought in Mexico during the Spanish-American War. His fame as a military strategist during the Civil War, when he was the commander of the Confederate armies, is well known. Although it is not always pointed out by historians he, like Grant, had financial difficulties after the civil War and was compelled to declare bankruptcy. By securing a post as president of Washington College, he was able to avoid additional poverty.(整體比較)
The same qualities that make people good houseguests make them good hospital patients. Good houseguests can expect a reasonable amount of service and effort on their behalf, and hospital patients can also. Guests have to adjust to what is for them a change, and certainly hospital patients must do the same. No one appreciates a complaining, unpleasant, unappreciative house guest, and the hospital staff is no exception. Hose guests who expect vast changes to be made for their benefit are not popular for long. Certainly nurses and other personnel with their routines feel the same way about patients in their care. Just as house guests must make adjustments to enjoy their visits, so patients must make adjustments to make their stays reasonably pleasant and satisfying under the circumstances.(逐項比較)
(6)原因和結(jié)果 因果分析是常用的拓展段落的方法之一，一定要注意推理的邏輯性因果關(guān)系必須表達(dá)清楚，不能因果混淆，更不能因果倒置，要避免牽強(qiáng)附會和循環(huán)論證。一個原因可能造成一個或多個結(jié)果，也可能在一大段文章中涉及到一連串因果關(guān)系。一個結(jié)果也可能由多種原因所引起，通常先寫結(jié)果，后寫多種原因；但也可先寫原因后寫結(jié)果。另外，如果喲啊強(qiáng)調(diào)原因或結(jié)果，可用倒裝或強(qiáng)調(diào)句型加以突出。例如：
The surge of demand for oil will soon begin to send shock waves through the American economy and transportation system. The impact of these tremors can already be anticipated: to the consumer they signal the end of a long love affair with the car, and to Detroit they offer an early warning that its 1985 growth aims are dangerously unrealistic. Unless we exercise foresight and devise growth-limits policies for the auto industry, events will thrust us into a crisis that will lead to a substantial erosion of domestic oil supply as well as the independence it provides us with, and a level of petroleum imports that could cost as much as $20 to $30 billion per year. Moreover, we would still be depleting our remaining oil reserves at an unacceptable rate, and scrambling for petroleum substitutes, with enormous potential damage to the environment.
(7)定義法 有時候為了避免混淆或誤解，我們必須對一個詞、一條術(shù)語或諺語、一個概念通過下定義加以說明、解釋。通常有三種方法下定定義：給出同義詞、用一個帶有定語從句的復(fù)合句或用一整段文章，而以第三種方法最為常用。1997年1月份四級考試的作文Practice Makes Perfect就是一篇極為典型的定義型文章。再看下面的例子：
A "liberated woman" is simply a woman who controls her own life, rather than allowing it to be controlled by other people, traditions, or expectations. A "liberated woman" can be found pursuing any line of work, including housework, or no work at all. She may or may not be married; she may or may not have born children. She may belong to any race; she may have attained any age. She need have only one trait in common with her "liberated sisters": she makes her own choices, whether they be the colors on her walls or the advanced degrees she seeks. She acts of her own volition, responsible to herself, and not out of fear of what her mother, lover, or neighbor might say.
