A-level经济供给与需求分析

学习A-level经济的小伙伴都知道，一般开篇的第一部分内容就是供给与需求，这是整个A-level经济的基础，其重要性不言而喻。今天来和同学们分享一篇关于这类知识点的data response。

With the help of an appropriate diagram and the information in Extract B, explain why the world price of wheat  changed in 2010.

首先我们来说说审题吧，抓住关键词“diagram”，既然提到了用表格分析，同学们在作答的时候务必要记得附上图像，因为图像也可以作为analysis的一部分。为了能够使采分点一目了然，我们可以采取“各个击破”的方式。关于Knowledge维度，我们可以从材料中找到相关的经济学概念，并且解释其含义，一般来说解释2-3个即可，以下是这一题中涉及的相关经济学术语及其解释。

其次，我们需要针对材料，对答案的内容和逻辑关系进行梳理。这里需要注意了，supporting details一定要从材料中找，这样才能把经济学理论知识和具体情境相结合。

关于供给和需求这一块的分析，我们建议大家使用logic chain的方式，这样不仅逻辑性强，调理清晰，也能为后续的答题列好提纲，不会遗漏答题要点。

关于evaluation这一块，同学们可以就题目中涉及到的主体，进行分析。可供选择的角度主要有：magnitude,potential,problems,solutions.当然，同学们也可以从相关的经济学理论入手，对现有经济学现象的前提条件进行讨论。因为前提条件的改变，很有可能会得出截然不同的结论。

以下为同学们提供了两个evaluation的角度可供参考。

Evaluation/Conclusion:

1. Adjustment process:

The excessive demand results from an increase in demand/ a decrease in supply, which leads to the price of wheat rising, followed by an extension of supply/a contraction of demand.

2. PES, PED

When the PES is inelastic, a rise in the price of wheat will cause a less increase in the quantity of wheat, or vice versa.When the PED is inelastic, a rise in the price of wheat will cause a greater decrease in the quantity of wheat, or vice versa.

Reference version:

Demand is the quantity of goods that consumers are willing to pay at any given price over a period of time. Supply refers to the quantity of goods that suppliers are willing to sell at any given price over a period of time.

For demand side, rising living standard causes a rise in the demand for meat, which leads to an increase in the demand for wheat because wheat can be used to feed animals. Besides, increasing demand for biofuel can generate a rise in the demand for wheat.

For supply side, bans on wheat exports will deacrease its supply. Furthermore, natural events like floods and droughts may result in a fall in the supply of wheat.

When it comes to process adjustment, there is an excessive demand resulting from an increase in demand/ a decrease in supply, which leads to the price of wheat rising, followed by an extension of supply/a contraction of demand.

As for  PES or PED, when the PES is inelastic, a rise in the price of wheat will cause a less increase in the quantity of wheat, or vice versa.When the PED is inelastic, a rise in the price of wheat will cause a greater decrease in the quantity of wheat, or vice versa.