高级医学英语阅读与写作Chapter two
2012-06-02 22:49:01   来源：37度医学网   作者：  评论：0 点击：

Since so many women have gone           the days of the “happy
            back to work,                                    housewife” are over.
 
     Because so many women have gone,             the days of the “happy
            back to work,                                   housewife” are over.
 
                 effect                                                   cause
     The days of the “happy house-                since so many women have
            Wife” are over                                          gone back to work.
 
     The days of the “happy house-                because so many women
            Wife” are over                                          have gone back to work.
 
Though those groups indicate the relationships in a sentence, the indicators in the third group are commonly used to indicate the relationship in a paragraph as in Sample A, in which the first half before the word “thus” is the cause, and the second part is of course the effect. 
 
Classification
 
When we divide a number of things into groups, classes, categories, etc., we are classifying those items. The classification is normally made according to a criterion or several criteria (standards or principles on which judgments are based). Paragraphs can be organized in this way.
There are two systems of classification; one is grouping and the other is division. By grouping is meant the arrangement of objects, people or ideas with shared characteristics into classes or groups. For example, you can classify motorcycles, cars and trucks as "motor vehicles"; apples, pears, and oranges as "fruits"; monarchy, democracy, and dictatorship as "political systems". And division, on the other hand, is the act of cutting up one big group into two or more smaller ones. The same is true that the political systems can be divided into monarchy, democracy and dictatorship.
Which system is used in the following paragraph, grouping or division?
 

 
Cells
Tissues
 
 
Organs
 
 
Systems
 
 
 
 
 
 
 
       Our body is made up of tiny, microscopic blocks called cells. Similar cells are grouped together in a regular fashion to form higher units known as tissues. Just as cells are grouped together to make tissues, tissues, in turn, are combined to form still higher and more complex units,the organs. Our eyes, brain, and nose are organs, and so are our heart, lungs and stomach. Lastly, a group of organs working together for the same function is called a system. The organ systems are nine in number, including the muscular, circulatory, respiratory, digestive, and others. The heart, blood and blood vessels form the circulatory system; and the lungs, nose and air tubes constitute the respiratory system. The brain, the spinal cord and the nerves make up the complex nervous system, by which the functions of all the parts of our body are controlled and well coordinated.

The answer to the question above is the grouping system of the classification. Now look at how the writer classifies hymenoptera:
 
Hymenoptera may be classified according to whether or not they have a ‘waist’. Those which have a waist are known as petiolata, a