三道微观经济学英文选择题，求解析！

1.Which one of the following would shift the supply curve for a good to the left?
A decrease in
A.demand for the good
B.subsidies granted to producers
C.the rate of growth of labour productivity
D.the elasticity of supply of the good

2.Which one of the following statements referring to a market economy is correct?
A.monopolists take no account of consumer perferences
B.prices do not always reflect social cost
C.efficiency is always indicated by high profits
D.large fims are more efficient than small firms

3.Two products are in joint supply when
A.a fell in the output of one product is accompanied by a decrease in the output of the other product
B.an increase in the demand for one product reduces the supply of the other product
C.a rise in the quantity supplied of one product reduces the supply of the other product
D.a fall in the price of one product reduces the cost of supplying the other product

答案是BBA，不知道对的选项对在哪，也不懂错的选项为什么是错，求教！

我做出了一些解释，如果看得过去的话，就设为最佳答案吧

1.Which one of the following would shift the supply curve for a good to the left?
A decrease in
A.demand for the good（与供给曲线无关，这是需求曲线的部分）
B.subsidies granted to producers（补贴减少了，同样价钱下，成本增加了，所以供给数量减少，曲线向左移动）
C.the rate of growth of labour productivity（劳动生产率的增长速度减缓，但仍然是增长，供给曲线依然向右移动）
D.the elasticity of supply of the good（弹性与供给曲线的位置无关，只描述的是价钱的变化对供给数量的影响）

2.Which one of the following statements referring to a market economy is correct?
A.monopolists take no account of consumer perferences（垄断可以控制市场价格给达到利益最大化，无需考虑顾客的偏好）
B.prices do not always reflect social cost（外部效应 (externality) 才反应的是社会成本，价格不一定包含社会成本，比如对环境的保护而增加成本来减少废水废气的排放）
C.efficiency is always indicated by high profits（高利润通常表示高效率，表示更好的控制成本）
D.large fims are more efficient than small firms（大公司的生产成本会比小公司小，所以更有效率）

3.Two products are in joint supply when
A.a fell in the output of one product is accompanied by a decrease in the output of the other product（这个是 joint supply 的定义，一个产品供应的变化，会造成其他（副）产品供应的同方向变化，比如说养牛的减少，会造成牛肉、牛奶等产品供应的减少）
B.an increase in the demand for one product reduces the supply of the other product（joint supply 与需求无关，只是强调的是供给的影响）
C.a rise in the quantity supplied of one product reduces the supply of the other product（与 joint supply 相反）
D.a fall in the price of one product reduces the cost of supplying the other product（与 joint supply 无关，仅仅是供给曲线上的移动）

cmwei333 发表于 2016-10-30 07:27
我做出了一些解释，如果看得过去的话，就设为最佳答案吧

1.Which one of the following would sh ...

求问
第一题 B选项 补贴减少了，为什么成本反而升高？补贴少了，生产者花出去的钱不就更少了吗？这样不是降低成本？
第二题 题目的意思是说选一个符合市场经济规律的答案吗？如果是，那ACD都是对的？为什么还选B呢？

bubiu903 发表于 2016-10-30 17:08
求问
第一题 B选项 补贴减少了，为什么成本反而升高？补贴少了，生产者花出去的钱不就更少了吗？这样不是 ...

第一题，我打错了，应该是“成本减少了”

第二题，我 C 和 D 搞错了，应该是

C.efficiency is always indicated by high profits（market efficiency 与利润无关）
D.large fims are more efficient than small firms（market efficiency 与公司大小无关）

market effiency 的定义是 “an economic state in which every resource is optimally allocated to serve each individual or entity in the best way while minimizing waste and inefficiency”。当经济达到 economically efficient 的时候，any changes made to assist one entity would harm another. In terms of production, goods are produced at their lowest possible cost, as are the variable inputs of production.  这里谈的是整体的经济状况，而利润与公司的大小是关于“会计”的。

A 选项是错的，因为垄断可以控制市场价格，但也要考虑消费者的偏好，不然与消费者的偏好不一致的话，就无法出售产品

只有 B 是对的，价格不一定包括外部性 (externality)，所以并不能反映社会成本

cmwei333 发表于 2016-10-30 17:22
第一题，我打错了，应该是“成本减少了”

第二题，我 C 和 D 搞错了，应该是

为什么低成本导致供应量减少呢？同等条件下，不是个体生产成本越低，总量越大吗

补贴减少就是生产者生产一个产品收到也许是ZF的补助少了，比如生产者生产一个产品要1000，但可以有200的补助，那么生产者的成本就是800，但是现在补助减少了，变为0了，那生产者的生产成本全都由生产者承担，成本增加，供给就减少了呀。