问题 问答题 简答题

为什么一段时间内消费的商品减少,其边际效用会增加?

答案

参考答案:

根据边际效用递减律,个人在增加他对同种商品和劳务的消费中,他增加的满足是递减的;反之,个人在减少他对同种商品和劳务的消费中,他减少的满足是递增的。例如,人们吃第二个馒头得到的满足要比第三个馒头大,而吃第一个馒头得到的满足要比第二个馒头更大。这是因为,消费一物品数量减少,人们越感到这种物品对满足自己需要的重要性。如果该物品有多种用途测一物品数量越少时,人们越会将此物品用来满足自己最迫切最重要的需要。

阅读理解

To get an extra 14 years of life, don’t smoke, eat lots of fruits and vegetables, exercise regularly and drink alcohol in a proper amount.That is according to a study published this Monday in the Public Library of Science Medicine Journal.

After tracking more than 20,000 people aged 45-79 years in the United Kingdom from about 1993-2007, Kay-Tee, Khaw of the University of Cambridge and his colleagues found that people who adopted these four healthy habits lived an average of 14 years longer than those who didn’t.

“We’ve known for a long time that these behaviors are good things to do, but we’ve not seen this benefit before, ” said Susan Jebb, head of Nutrition and Health at Britain’s Medical Research Council.“The benefit was also seen regardless of whether or not people were fat and what social class they came from.”

Study participants(参与者) scored a point each for not smoking, regular physical activity, eating five servings of fruits and vegetables a day and moderate alcohol intake.

Public health experts said they hoped the study would inspire governments to introduce policies helping people to adopt these changes.But because the study only observed people rather than testing specific changes, it would be impossible to conclude that people who suddenly adopted these healthy behaviours would surely gain 14 years.

“We can’t say that any person could gain 14 years by doing these things,” said Doctor Tim Armstrong, a physical activity expert at the World Health Organization.”The 14 years is an average across the population of what’s theoretically(理论上) possible.”

“Most people know that things like a good diet matter and that smoking is not good for them”, Susan Jebb said, ”We need to work on providing people with much more practical support to help them change.”

1.Which of the following doesn’t belong to the four healthy habits?

A.Eating five servings of fruits and vegetables a day.

B.Doing proper exercise in the morning every day.

C.Having a cigarette before going to bed every day.

D.Drinking alcohol in the proper amount every day.

2.We can learn from the passage that_____.

A.the study observed people as well as tested specific changes

B.Susan Jebb did not take part in the study

C.there is no need for people under 45 adopt these good habits

D.only those from first class can benefit from these healthy behaviours

3.What can be inferred from the passage?

A.Governments should take measures to help people change their bad habits.

B.People aged 45-79 have bad habits in the United Kingdom.

C.All the people are well aware of the harm of their bad habits.

D.People have adopted the four healthy habits after knowing they’re good.

4.What would be the best title for this passage?

A.Smoking and Drinking Cuts You 14 Years

B.Healthy Habits Could Gain You Extra 14 years

C.A New Way of Keeping Healthy

D.Smoking and Drinking Harms Your Health

单项选择题