Law of Supply & Demand:
供求规律：
This is the founding block of economics.
这是经济学的基石。
Whenever supply of something increases its price decreases and whenever supply decreases price increases.
物品供给增长则价格下跌，供应减少则价格上涨。
Thus, when you have excess production of corn, food prices decrease and vice versa.
因而谷物产量过剩，食物价格则下降；反之亦然。
Think of this intuitively. You will find its applications in 1000s of places.
凭直觉判断，你会发觉这条定律适应于千千万万个地方。
Growth rate:
增长率：
The growth of an economy is commonly measured in terms of GDP growth rate.
经济体的增长一般是依据国内生产总值增长率来衡量的。
Since GDP is a measure of national income, this growth rate is a rough proxy for how an average person's income grows every year.
国内生产总值衡量国家的收入，所以增长率可以粗略衡量平均每人每年收入增长多少。
Inflation:
通货膨胀：
You already know that the price of most products now are higher than in your grandfather's time.
你知道现在大部分产品的价格比你祖父那时要高得多。
Inflation (measured in percent) is measure of how much a bunch of products have increased in price from last year.
通货膨胀（以百分比计）衡量自上一年起众多产品价格的涨幅。
In mature economies, annual inflation is around 2% - that means on an average the prices of stuff goes up by 2% every year.
成熟的经济体每年的通货膨胀率约为2%——即物品价格平均每年上涨2%。
The fundamental role of central banks is to manage this rate and keep it to a low positive number.
中央银行的基本作用即控制通胀率，确保其增长呈小幅态势。
Interest Rates:
利率：
When you loan money to somebody, you expect something extra in return. This excess is called the interest.
你借钱给别人时，你便会有额外的期待，这额外的部分就是利息。
Interest rate is a positive number that measures how much excess you will get.
利率是衡量你额外获益多少的一个正数。
In the short term, this rate is usually set by the Central Banks.
从短期来看，利率通常是由央行规定的。
Right now it is close to zero. In the long term, this is set by the market and is dependent on inflation and the long term prospects of the economy.
现在短期利率接近于0；从长期来看，利率是由市场决定的，取决于通货膨胀和长远的经济前景。
The mechanisms in which the central banks control the short term rates is called monetary policy.
央行控制短期利率的机制就叫做货币政策。
Interest Rates vs. Inflation vs. growth:
利率、通货膨胀和增长：
There exists almost an inverse relationship between interest rates & growth and interest rates also can affect inflation directly.
利率和增长呈反相关，利率也会直接影响通货膨胀。
Thus, when you increase interest rates inflation tend to come down, along with growth.
因此，提高利率时，通货膨胀会趋向缓和，增长也是如此。

One is good and other is bad.
一方得势，另一方就失势。
Thus, the constant tension on setting the interest rates.
因此，利率的规定有恒定的张弛。
In the US, Federal Reserve sets the short term rates making it one of the most watched economic news.
在美国，美联储制定短期利率是最受关注的经济新闻之一。
Fiscal Policy:
财政政策：
Government can control the economy in a big way by adjusting its expenditure.
政府能够通过调整开支大力控制经济。
The group of mechanisms using expenditure form the fiscal policy.
花销机制形成财政政策。
When government spends more it can lead to more demand and that means more price increase. This means both high growth and high inflation. And it works in the reverse too.
政府支出更多时，则会导致更大需求，即更多价格上涨，这也意味着高增长和高通胀；反之亦然。
Thus, governments try to spend more during periods of low growth & low inflation and cut spending during periods of high growth & high inflation.
因此，在低增长和低通胀期间政府就会设法加大开支，而在高增长和高通胀期间政府就会削减开支。