如何用比较与对照法推展篇章
24．1 Comparison and Contrast（比较与对照）
Often we may want to describe several aspects of two subjects that have both similarities and differences．When we compare two things，we show how they are similar；when we contrast two things，we show how they are different．We may compare or contrast two schools，two cars，two friends，two jobs，two cities，etc．．For this purpose，we may employ the combined techniques of comparison and contrast．In writing the essay，you should always bear two important decisions in mind：①Whether you are to do a comparison，a contrast，or a mixture，or②Whether you are to use an item-to-item（逐事比较）or point-to-point（逐点比较）method of development（both have been explained and illustrated in Unit14）
Model Essay 24-1
Shanghai and New York are two of the biggest cities in the world．They are different in some ways，but they are similar in some other ways．
Shanghai is one of the most densely populated cities in Asia，and New York is one of the most densely populated cities in North America．The population of Shanghai is homogenous，but thepopulation of New York is heterogeneous．The people in Shanghai speak Chinese；the people in New York speak English instead．The cost of living in Shanghai is generally low in comparison with that in New York．While the people in Shanghai take buses or ride bikes to go to work，the people in New York drive cars or take subways to get to work．The people in Shanghai use fans to keep cool，where as the people in New York use air-conditioning．
Both Shanghai and New York are cities of GREat wealth and poverty．In both cities，there is a great deal of beauty and a great deal of ugliness．Many people in Shanghai are as kind and helpful as those in New York．Conversely，some people in Shanghai are as dangerous as those in New York．In both cities，there are people who work all day and people who work all night．Both cities are never asleep．
To some visitors，both Shanghai and New York are a paradise and a jungle．
24．2 Analysis of the Model Essay（范文分析）
From the above point-to-point essay，we can see that the similarities and differences of Shanghai and New York are as follows：
①Differences：
a．population
（homogeneous S
（heterogeneous NY
b．language
（Chinese S
（English NY
C．cost of living
（low S
（high NY
d．transportation
（buses and bikes S
（cars and subways NY
e．cooling appliances
（fans S
（air-conditioning NY
②Similarities：
a．both are most densely populated
b．both are cities of GREat wealth and poverty
c．both are beautiful and ugly
d．both have kind and helpful people and dangerous people
e．both are never asleep
通过以上比较和对照法的结合使用，作者巧妙地将与主题有关的五个异同点联系在一起，交替进行逐点比较、对照，这使得读者从始至终能够把握比较与对照的线索。而且，作者又在比较与对照的结构上灵活地安排了次序，使对比既鲜明突出，又富有变化；作者还通过不同的连接手段，如并列连词“and，both，as…as”，与转折连词“but，instead，while，whereas，in comparision with”等，使得比较与对照自然流畅，前后连贯。
