如果让Aevel考生选择ALevel科目，ALevel经济就是首选的热门科目，而Exchange rate作为ALevel经济的难点之一，让很多考生备考难度大大提升，那么几天小编就为大家讲解一下Exchange rate的知识点！
1. definition 定义
Nominal exchange rate 名义汇率:
This is the weight of one currency relative to another, withoutbeing adjusted for inflation.
Real exchange rate 实际汇率:
This is when the exchange rate is adjusted for inflation to give a moreaccurate reflection of purchasing power.
Trade-weighted exchange rate 贸易加权汇率:
This is the weighted average of the exchange rate, of thedomestic currency relative to foreign currencies, where theweight of each currency is equalto the share in trade. The more the domestic country trades with a foreign country, thegreater the weight of the currency.
2.The determination of exchange rates 汇率的决定因素
Floating exchange rate 浮动汇率由供需决定:
The value of the exchange rate in a floating system is determined by the forces of supply and demand.
Fixed exchange rate 固定汇率由government决定:
A fixed exchange rate has a value determined by the government compared to other currencies.
Managed float exchange rate 管理浮动汇率（介于以上二者之间，自由浮动，但是也有governments的干预）:
This occurs when the exchange rate floats on the market, but the central bank of the country buys and sells currencies to try and influence their exchange rate.
3.Depreciation and appreciation 汇率的升值与贬值
Depreciation 贬值:when the value of a currency falls relative to another currency, in a floating exchange rate system.
Appreciation 升值:when the value of a currency increases. Each pound will buy more dollars, for example.
4.The factors underlying changes in exchange rates 影响汇率变化的因素
1. Inflation 通货膨胀:
A lower inflation rate means exports are relatively more competitive. This increasesdemand for the currency. This causes the currency to appreciate.
2. Interest rates 利率:
An increase in interest rates, relative to other countries, makes it more attractive toinvest funds in the country because the rate of return on investment is higher. Thisincreases demand for the currency, causing an appreciation. This is known as hotmoney.
3. Speculation 投机行为:
If speculators think a currency will appreciate in the future, demand will increase inthe present, since they believe a profit can be made by sellingthe currency in thefuture. This can cause an increase in the value of the currency.
4. Other currencies 其他货币:
If markets are concerned about major economies, such as the EU, the currency might rise. This happened with the Swiss Franc in 2010 when markets were worried about the EU economy.
5. National debt 国债:
A government with a high level of debt is at risk of defaulting, which could cause thecurrency to depreciate. This is since investors start to lose confidence in theeconomy, so they sell their holdings of bonds.
6. Balance of payments 国际收支:
When the value of imports exceeds exports, there is a current account deficit.Countries which struggle to finance this, such as through attracting capital inflows,have currencies which depreciate as a result.
7. International competitiveness 国际竞争力:
An increase in competitiveness increases demand for exports, which increasesdemand for thecurrency. This causes an appreciation of the currency.
8. Government intervention 政府干预:
Governments might try and influence their currency, such as by maintaining a fixedexchange rate.
5. The effects of changing exchange rates on the domestic and external economy 汇率变化对于国内外经济的影响
1. Marshall-Lerner condition and the J-curve effect
The Marshall-Lerner condition states that a devaluation in a currency only improves thebalance of trade if the absolute sum of long runexport and import demand elasticities isgreater than or equal to 1.
The J-curve effect occurs when a currency is devalued. Since devaluing the currency causesimports to become more expensive, at first the total value of imports increases, which
worsens the deficit. Eventually, the value of exports increases, which leads to a reduction inthe trade deficit.
When the currency is devalued, there may be a time lag in changing the volume of exportsand imports. This could be due to trade contracts and the price inelasticity of demand forimports in the short run, whilst consumers search for alternatives. In the long run,consumers might start purchasing domestic products, for example, which helps improve thedeficit.
长期来看，货币贬值使得出口商品价格下降，因此出口总值会增加。此外，进口商品价格上升，消费者对于进口商品的需求也会下降。这两个因素使得current account deficit经常账目赤字得以改善，甚至变成current account surplus。
2. The effect of exchange rates on AD
Exchange rate affects AD because they affect the price of exports and imports. If theexchange rate appreciates, AD is likely to fall since imports become cheaper and exportsbecome more expensive.