Another common type of reasoning is the search for causes and results. We want to know whether cigarettes really do cause lung cancer, what cause malnutrition（营养不良）, the decay of cities, or the decay of teeth. We are equally interested in effects: what is the effect of sulphur or lead in the atmosphere, of oil spills and raw sewage (污水、污物）in rivers and the sea, of staying up late on the night before an examination?

注：

1.reasoning 推理

2.第一句 Another...下结论，是主题句

3.第二、三句 We want to ...an examination?是举例,可以略读

4.malnutrition 中“mal”是表示“不好”的前缀；overnutrition 营养过剩

Causal reasoning may go from cause to effect or from effect to cause. Either way, we reason from what we know to what we want to find out. Sometimes we reason from an effect to a cause and then on to another effect. Thus, if we reason that because the lights have gone out, the refrigerator won't work we first relate the effect (lights out) to the cause (power off) and then relate that cause to another effect. This kind of reasoning is called, for short, effect to effect. It is quite common to reason through an extensive chain of causal relations. When the lights go out we might reason in the following causal chain: lights out-power off-refrigerator not working -temperature will rise-milk will sour. In other words, we diagnose （判定）a succession of effects from the power failure, each becoming the cause of the next.

注：

1.causal 原因的，因果关系的

2.三种推理方式：从原因到结果、从结果到原因、从结果到原因再到另一个结果，第三种更重要

3.extensive 广泛的，来自extend延伸 extensive reading 泛读

4.In other words 换而言之 a succession of 一系列

5.本段讲关系链

Causes are classified as necessary, sufficient, or contributory（起辅助作用的）. A necessary cause is one which must be present for the effect to occur, as combustion (燃烧)，is necessary to drive a gasoline engine. A sufficient cause is one which can produce an effect unaided (独自的), though there may be more than one sufficient cause: a dead battery is enough to keep a car from starting, but faulty spark plugs（火花塞）or an empty gas tank will have the same effect. A contributory cause is one which helps to produce an effect but cannot do so by itself, as running through a red light may help cause an accident, though other factors --- pedestrians (行人) or other cars in the intersection-must also be present

注：intersection 交叉路口 inter+section

In establishing or refuting (驳斥，反斥) a causal relation it is usually necessary to show the process by which the alleged (所宣称的，所指称的) cause produces the effect. Such an explanation is called a causal process.

注：在证实或驳斥因果关系需要把推理过程显示出来，如灯灭了，牛奶变酸：灯灭了-停电-冰箱不工作-温度上升-牛奶变酸

1. What the author discussed in the previous section is most probably about ____.

A) relationships between causes and results

B) classification of reasoning

C) some other common types of reasoning

D) some special type of reasoning

注：文章之前的段落内容=首句+结构提示词，one-the other/some-another

Another common type of reasoning is the search for causes and results. We want to know whether cigarettes really do cause lung cancer, what cause malnutrition（营养不良）, the decay of cities, or the decay of teeth. We are equally interested in effects: what is the effect of sulphur or lead in the atmosphere, of oil spills and raw sewage (污水、污物）in rivers and the sea, of staying up late on the night before an examination?