黑色星期二
The longest and most serious economic downturn in modern history was the Great Depression.
「經濟大蕭條」是現代史上歷時最長且最為嚴重的經濟衰退，
serious(adj.)嚴重的downturn(n.)經濟衰退
It began in the United States in 1929 and spread worldwide, lasting until about 1939.
1929年美國率先爆發經濟蕭條，後來擴及全球，直至1939年才結束。
spread(v.)擴散;散播worldwide(adj.)(adv.)全球性的last(v.)持續;延續
There were a number of factors that led to the Great Depression, and the most significant one is a day known as “Black Tuesday.”
有幾項原因導致經濟大蕭條，其中最重要的是被稱為「黑色星期二」的一天，
a number of sth.=幾個...lead to=導致significant(adj.)顯著的;重要的The government has made significant changes to the current law.be known as...=以...為人知曉
On that day, investors began “panic selling,” resulting in the stock market crash of 1929.
當天投資者開始「恐慌拋售」，引發1929年股市崩盤。
investor(n.)投資者panic(n.)(v.)恐慌panic buying=因恐慌而搶購When the earthquake hit, she ran out in panic.result in=導致;造成His bad temper has resulted in several unsuccessful relationships.
Following the crash, as people worried about the future of the economy, they started to cut down on spending.
股市崩盤後，由於擔憂經濟前景，老百姓開始大幅減少消費，
cut down on sth.=減少...
As a result, industrial production dropped 47 percent, and the GDP fell 30 percent.
結果工業生產減少了47%，國內生產毛額（GDP）跌了三成，
as a result=(作為)結果GDP=Gross domestic product
Ultimately, many people lost their jobs. The unemployment rate even exceeded 20 percent at the height of the depression.
最後許多人失業，在大蕭條最嚴重的時候，失業率甚至衝破20％。
unemployment(n.)失業The country’s unemployment rate has increased sharply.exceed(v.)超過;超出at the height of sth.=~的高峰Springtime is the height of the tourism season.
The gold standard, which is a system that measures the standard unit of currency to a fixed quantity of gold, linked other countries’ currencies to the U.S. dollar and played a major role in spreading the downturn globally.
金本位制將他國貨幣與美元綁在一起，進一步將經濟衰退擴及全球，金本位制是指各國貨幣的價值，取決於該貨幣的含金量的一項制度。
measure(v.)測量;估量;衡量currency(n.)貨幣Shells were used as a currency in the past.play a role in...=扮演...角色;擔任...功能globally(adv.)全球地
The Great Depression ended in most countries by 1933, but many countries did not fully recover until the late 1930s or early 1940s.
多數國家在1933年前結束了經濟大蕭條，但許多國家的經濟直到1930年後期或40年代初期才真正復甦。
not...until...=直到...才...recover(v.)恢復;復甦