经济学原理I(10秋季期中1)

经济学原理I （2010年秋季学期）

期中考试1（A 卷答案）

（2010/11/3）

注意：请将所有题目的答案写在答题册上，写在本试题纸上一律无效。

一、判断题（判断并简要说明理由，必要时可以用图形。每题4分，共20分）

1. 假设你捡到了20美元，并选择用它购买一本小说。则你购买这本小说的机会成本是零。 错误。你购买小说的机会成本是用这20美元购买其他物品或服务带给你的好处（可能大于或等于20美元。（注：答20美元也算对）

2. 电脑行业的技术进步只能使得经济中的电脑产量增加，而经济中其它产品的数量不会增

加。

错误。电脑行业的技术进步使得整个社会的生产可能性边界外移（如图）。一般来说，这会使得社会可以生产的其他产品的数量也增加（如图中A 到A’点）。直观来说，由于技术进步，当社会在既定的生产要素配置下可以生产更多电脑和同样多的其他产品时（图中B 点），通过生产要素重新配置也可以同时生产更多的两种产品（图中B 到A’点）。

3. An increase in the demand for notebooks raises the quantity of notebooks demanded but not

the quantity supplied.

False. The increase in demand for notebooks results in an increased quantity supplied, in general. The reason is that demand increase will raise the price (to eliminate the shortage it causes), which in turn increases the quantity supplied. The only way the statement would be true is if the supply is perfectly inelastic.

4. If more Americans go on a low-carb diet, the demand for bread will fall. The decrease in the

demand for bread will cause the price of bread to fall. The lower price, however, will then increase the demand. In the new equilibrium, Americans might end up consuming more bread than they did initially. (DO use a diagram to illustrate your explanations)

False. When the demand falls, there will be a surplus of bread for a while (FE 1 in the graph), when the original equilibrium price P 1 has not fallen yet. As time goes on, price begins to fall, quantity 电脑

其他产品

demanded (not demand itself) decreases and quantity supplied increases, just to eliminate this surplus. Finally the new equilibrium (E 2) will have a lower quantity demanded (and supplied), Q 2, and also a lower price, P 2.

5. 完全竞争市场上的单个企业可以通过将价格降低到市场现行价格之下来增加利润，因为

这样一来可以吸引更多的买者。（提示：完全竞争市场上的企业在现行价格下想卖多少就可以卖多少。）

错误。反证法。假定降低到某一价格P’后企业选择产量Q’可以取得更大利润。则在原来的市场价格P>P’下，企业也可以选择这一数量Q’并取得高于降价后的利润。矛盾。

二、选择题（每题3分，共42分。每题只有一个正确答案。）

1. The company that you manage has invested $5 million in developing a new product, but the

development is not quite finished. At a recent meeting, your salespeople report that the introduction of competing products has reduced the expected sales of your new product to $3 million. What should do?

A. You should go ahead to finish development and make the product if and only if it would cost

less than $5 million to do so.

B. You should go ahead to finish development and make the product if and only if it would cost less than $3 million to do so.

C. You should go ahead to finish development and make the product if and only if it would cost

less than $2 million to do so.

D. You should not go ahead to finish development and make the product at all.

2. 中国的“道路交通安全法”曾经将机动车与行人之间交通事故造成的损害由机动车与行

人分担，改为机动车全部承担。这导致机动车与行人相遇时，机动车驾驶员的谨慎程度 ；行人的谨慎程度 ；最终导致机动车与行人之间交通事故的可能性 。

A. 提高；提高；降低。

B. 降低；降低；提高。

C. 提高；降低；可能提高可能降低。

P 1

Q 2P 2 Q 1