Essay写作中每年必考Alevel经济考点elasticity的解析

　　如果对AS的经济真题进行分析，我们会发现，在Paper 2的essay里，elasticity（弹性）几乎是每年必考Alevel经济考点，因此如果对这块知识点掌握得很好，那么AS阶段的alevel经济Essay想拿高分其实很简单！

　　让我们来看一道2018年冬季Section B的真题。

　　我们在动笔写essay之前要有一个逻辑框架。对于这种8分且命令词是explain的题，其答题框架很简单，大致如下：

　　Structure：

　　P1：Define key terms（PES）

　　Body P2：Explain factor 1

　　P3：Explain factor 2

　　P4：Explain factor 3

　　有了框架之后，就需要考虑内容该写什么了。这道题很常规，是相关章节基础知识点的考察，学生们只要掌握好PES的概念、计算公式，经济意义和影响PES那几大因素就能做答了，当然我们在essay的写作中，一定要注意内容的完整性还有不要答偏题了。以下答案供同学们参考学习。

　　Define：Price elasticity of supply[PES]measures the degree of responsiveness in quantity supplied of a good due to a change in the price of the good itself.It is measured by PES=%∆QS/%∆P.A good is said to be elastic PES when a change in price leads to a more than proportionate change in the quantity supplied.The value of PES is more than one.Inelastic PES means a change in price will lead to a less than proportionate change in quantity supplied.The value of PES is between zero and one.

　　Body

　　1.Factor:Availability of spare capacity.When the level of production is at,or near,the level of full capacity,then,the supply of the good is likely to be inelastic PES.An increase in price will not be follow by the increase in supply due to capacity constraint.For example,if the factory is producing at full capacity,and increase in price of the good will not lead to increase in supply.The capacity will need to be raised before increase in output can materialized.

　　2.Factor:Time of production.If the good in question require a long period of production,for example agricultural good,then,the supply of the good is likely to be inelastic.The supply of the good cannot be increased in the short term,as time is required for the output to grow.Manufacturing goods,in general,are more elastic in PES due to the shorter period in the production process.

　　3.Factor:Mobility of factors.If the factors of production can be easily switched from producing one good to another,then,the PES will be more elastic.A higher price in jeans(clothing)can be matched by higher quantity as the material and machine can be easily switched to produce jeans from other clothing products.While an increase in the price of rubber,cannot be matched by increase in supply,as the rubber trees can only produce rubber and cannot produce any other things.Oil palm plantation can be switched to rubber plantation,though it will incur high cost and long period.

　　关于Alevel经济考点elasticity的讲解就到这里了，如果同学们在Alevel学习中还有什么问题，欢迎随时咨询我们！