Cause and Effect
①In our daily conversation, questions with why? are often asked and answered. This shows that causal analysis is very common； it is something we are familiar with.
②Sound reasoning or logic is naturally the most important quality of any causal analysis. But it is not always easy to explain causes and effects clearly and logically. One reason for this is that an effect may have many causes and a cause may have many effects. So we must have be thorough in our discussion and careful in our selection of details.
③There are two basic ways of organizing paragraphs developed by cause and effect.
④The first method is to state an effect and devote the rest of the paragraph to examining the causes. For example, the topic sentence is： "In the past few years, higher education has become less important to young people than it was previously. "This is an effect. It should be followed by a discussion of the causes of this effect, such as the pressure of fierce competition, better opportunities in the job market, much of the knowledge taught in universities and colleges being outdated, and so forth.
⑤The second method is to state a cause and then mention or predict the effects. Suppose the topic sentence is: M More and more fertile land in China is taken up by new buildings. "In the rest of the paragraph the effects of this development should be mentioned, such as the reduction of the grain output, increasing environmental problems, too many peasants moving into the cities, etc.
21.Questions with why are often asked and answered in our daily conversation, which shows that _______.