1.比较与对照的基本定义
比较(comparison)主要是指出两个或两个以上不同种类的共同点或相似点(similarities)，如人物、事物、地点、思想、观点等。对照(contrast)主要是指它们的不同点(difference)。在大学英语中，比较和对照法往往同时使用。写作时，首先应考虑要比较和对照的两个或两个以上的事物， 然后列一个表，发现这些事物的最主要特征，相同的或类似的特征可以比较，不同的特征可以组成对照。例如：
例1.Punctuality is the main constituent of good character.Aperson，who is always in time for his appointment，shows real considerationfor others.On the other hand，a person who is always lateshows his selfishness and thoughtlessness and he is not worthy tobe friend with.(本段对守时(in time)与不能守时(late)的两种不同的人进行了对照， 用表示对照的连接词“On the otherhand”进行了很好的连接。)。
例2.Paintings and photographs have something in common.But there are also some differences between them.(这段很好地展示出本文将用比较与对照的方法进行写作。)
Paintings and photographs are visual art forms.They both cancapture a specific moment for all time.A painting reflects the skilland talent of a painter，likewise the quality of a photograph canrepresent the skill and talent of a photographer.(本段对paintingsand photographs两个不同的种类进行了分析， 用连接词(both)进行了很好的连接，用连接词(likewise)用同样的方式对它们的相同点(the skill and talent)进行了比较)。
Photographs are created by using film，a camera，and specialpaper.In contrast，paintings are created with paint，brushes，andcanvas.Photographs，like paintings，are often framed and displayedon walls in homes and galleries.Both can vary in size.However，photographs are usually small enough to keep in albumswhere they document family events. ( 本段比较和对照法同时使用)。In conclusion，although paintings and photographs are similarin some ways，there are also some differences between them.(本段对本文的比较与对照进行了小结)。
2.比较与对照的两种基本写作方法
2.1整体对比法(one-side-at-a-time method)
整体对比法：既先描述甲，再描述乙(A1，A2，A3，...B1，B2，B3，...)例 如大学英语作文“Where to live———In the City or inthe Countryside” 第一段可描述几点城市生活(A1，A2，A3，...)，第二段可描述几点农村生活(B1，B2，B3，...)，用整体对比法写作。
例3.Many people appreciate the conveniences of the city.
(A).The city has better transportation service and health care.Citydwellers can easily enjoy themselves in restaurants，departmentstores and concert halls.They are well-informed about what is goingon at home and abroad，and have the access to better education，better jobs and more opportunities for business. (A1，A2，A3，...)But country life is also attractive. (B).Country people are inclose contact with nature.They breathe fresh air and listen to thesong of the birds.They make friends with crops and trees，cows andsheep.And they enjoy the peace and calm of the pastoral environment.(B1，B2，B3，...)
However，both the city and the country have their own disadvantages.The city，despite all its good points，may be a place toocrowded for people to live in.And urban citizens are often underpressure，worrying over such problems as pollution，crime and unemployment.(A1，A2，...).As for rural inhabitants，they are freefrom becoming layoffs all right，yet they may find life far from thecity less convenient，and sometimes not as colorful or full of vigor.
(B1，B2，...)
2.2逐项对比法(point-by-point method)逐项对比法： 既双方同时描述， 逐点进行比较(A1，B1;A2，B2;A3，B3...)
例4.Riding a bicycle has a lot of advantages over driving acar.First，it is a physical exercise to ride a bicycle. (A1).In contrast，sitting in the car，one tends to gain weight.(B1).Besides，it ismuch more economical to ride a bike than drive a car.On the otherhand，the only fee a bike-rider has to pay is the annual tax.However，the annual fees for a car are costly. (A2，B2).On the otherhand，a bike needn’t be equipped with a parking lot，but a carmust.(A3，B3).Most important of all，it is beneficial to the environmentto ride a bicycle because the bike doesn’t consume petrol;itis a pollution -free transport.In contrast，the exhaust released bythe car is harmful to the environment.(A4，B4).
3.常用于比较与对照写作方法的过渡连接语
要写好大学英语作文，使作文连贯、流畅，有条理，逻辑性强，灵活运用过渡连接词至关重要。如无连接词，作文实质上是一堆简单句的拼凑，读起来也枯燥无味。另外，过渡词也是信息词，能较好地表明作者想比较或对照的意图。
