请问费费#27

iselibra

27. These days, drug companies and health professionals alike are focusing their attention on cholesterol in the blood. The more cholesterol we have in our blood, the higher the risk that we shall die of a heart attack. The issue is pertinent since heart disease kills more North Americans every year than any other single cause. At least three factors---smoking, drinking, and exercise—can each influence levels of the cholesterol in the blood.
Which one of the following can be properly concluded from the passage?
(A) If a person has low blood cholesterol, then that person’s risk of fatal heart disease is low.
(B) Smoking in moderation can entail as great a risk of fatal heart disease as does heavy smoking.
(C) A high-cholesterol diet is the principal cause of death in North America.
(D) The only way that smoking increases one’s risk of fatal heart disease is by influencing the levels of cholesterol in the blood.
(E) The risk of fatal heart disease can be altered by certain changes in lifestyle.

E中所说的是危险可以被改变，而原文中仅仅是说“至少三种因素”，并非全部阿。
同时，“The more cholesterol we have in our blood, the higher the risk that we shall die of a heart attack.”是否也就是，The less cholesterol we have in our blood, the lower the risk that we shall die of a heart attack.不就是A么

miejue

以下是引用iselibra在2003-10-5 0:30:00的发言：
  同时，“The more cholesterol we have in our blood, the higher the risk that we shall die of a heart attack.”是否也就是，The less cholesterol we have in our blood, the lower the risk that we shall die of a heart attack.不就是A么

Attention！A-->B 不等于 not A --> not B   如男人是花心的 不等于 女人是不花心的。但是却可以推出 not B--> not A 就是不花心就不是男人。

针对这题就是the lower the risk that we shall die of a heart attack， The less cholesterol we have in our blood。推论中的逻辑关系不能随便变动的。

E说可以改变就是说可以通过改变任何一种因素而使risk发生变化，这里没有说使这种风险从可以引起心脏疾病变动到不引起心脏疾病，但只要变动了就符合原论断了。

iselibra

I see
thanks for ur help,miejue

miejue

Welcome!