原文来源：http://www.cfr.org/cuba/us-cuba-relations/p11113

On April 11, 2015, Presidents Barack Obama and Raúl Castro shook hands at the Summit of the Americas in Panama, marking the first meeting between a U.S. and Cuban head of state since the two countries severed their ties in 1961.

summit

1) N-COUNT  A summit is a meeting at which the leaders of two or more countries discuss important matters.
 ...next week's Washington summit.
 ...the NATO summit meeting in Rome.

2) N-COUNT  The summit of a mountain is the top of it.
...the first man to reach the summit of Mount Everest.

Sever one's ties

1. [I,T] to cut through something completely, separating it into two parts, or to become cut in this way 切断，割断

2. [T] to end a relationship with someone, or a connection with something, especially because of a disagreement  与…断绝（关系）:

  sever ties / relations / connections / links etc (with / between sb)

  The two countries severed diplomatic relations. 这两个国家断绝了外交关系。

  She had severed all contact with her ex-husband. 她和前夫断绝了一切往来。

造句：Having been severing the ties between he and me for couples of years, he didn't even know I was married last month.

造句：After she strongly criticized his impulsive decisions, instead of severing their ties, they started to talk more and more and became good friends.

The meeting came four months after the presidents announced their countries would restore diplomatic relations, and gave rise to President Obama's March 2016 visit to Cuba, the first by a sitting president in over eighty-five years.

give rise to

21) PHRASE:  V inflects, PHR n   If something gives rise to an event or situation, it causes that event or situation to happen.
Low levels of choline in the body can give rise to high blood-pressure...

造句：His carelessness eventually gives rise to his losses to property.

Syn: provoke

The change in the countries' relations, initially marked by a prisoner swap and Havana's release of a jailed U.S. subcontractor in December 2015, prompted some experts to point to better prospects for Cuba’s economy and U.S.

swap

noun *an act of exchanging one thing for another

let's do a swap

*a thing that has been or may be given in exchange for something else

I've got one already, but I'll keep this as a swap

*Finance: an exchange of liabilities between two borrowers, either so that each acquires access to funds in a currency they need or so that a fixed interest rate is exchanged for a floating rate

But the U.S. trade embargo, which requires congressional approval to be rescinded, is unlikely to be lifted any time soon.

rescind

1. to officially end a law, or change a decision or agreement  废除; 取消; 撤销

The tumultuous U.S.-Cuba relationship has its roots in the Cold War.

tumultuous

1. full of activity, confusion, or violence  混乱的，骚乱的，乱哄哄的:

the tumultuous years of the Civil War

2. very loud because people are happy and excited  嘈杂的，吵闹的，喧哗的:

He received a tumultuous welcome. 他受到了热烈欢迎。

tumultuous applause 热烈的掌声

兩個意思：一個褒義一個貶義。

However, as Castro's regime increased trade with the Soviet Union, nationalized U.S.-owned properties, and hiked taxes on American imports, the United States responded with escalating economic retaliation.

hike

4) VERB  To hike prices, rates, taxes, or quantities means to increase them suddenly or by a large amount. [INFORMAL]

 [V n  ] It has now been forced to hike its rates by 5.25 per cent...

 [V n  ] TSB's monthly credit card rate is now hiked from 1.95% to 2.05%...

retaliation

1. action against someone who has done something bad to you  报复，反击;

⇨ revenge :

in retaliation (for sth)

This action was undoubtedly in retaliation for last week's bomb attack.

这个行动无疑是对上周炸弹袭击事件的报复。

[+ against ]

the threat of massive retaliation against British troops

要对英军进行大规模报复的威胁

After slashing Cuban sugar imports, Washington instituted a ban on nearly all exports to Cuba, which President John F. Kennedy expanded into a full economic embargo that included stringent travel restrictions.

slash

2. [T] to greatly reduce an amount, price etc – used especially in newspapers and advertising  大幅度削减〔数量、价格等; 尤用于报纸及广告中〕;  SYN  cut

The workforce has been slashed by 50%.  劳动力已削减了 50%。

The 1961 Bay of Pigs invasion, a botched CIA-backed attempt to topple the government, fueled Cuban mistrust and nationalism, leading to a secret agreement allowing the Soviet Union to build a missile base on the island.

botch 动词作形容词

1. to do something badly, because you have been careless or because you do not have the skill to do it properly〔因不经心或缺乏技术而〕把…做得拙劣:

  The builders really botched up our patio. 建筑工人把我们的露台做得一塌糊涂。

  a botched investigation 敷衍了事的调查

noun.

a piece of work, a job etc that has been badly or carelessly done 拙劣的活儿:

topple

1) V-ERG  If someone or something topples somewhere or if you topple them, they become unsteady or unstable and fall over.

 [V adv/prep ] He just released his hold and toppled slowly backwards...

 [V n  ] Winds and rain toppled trees and electricity lines. [Also V ]

PHRASAL VERB Topple over

[V n  ] ...the revolution which toppled the regime.

Syn: overthrow

fuel

1. [T] to make something, especially something bad, increase or become stronger

  使恶化; 使更强烈:

  His words fuelled her anger still more. 他的话火上浇油，使她更愤怒了。

  fuel speculation / rumours / controversy / mistrust etc

  Progress was slow, fueling concerns that the stadium would not be finished on time.

  进度很慢，加深了人们对体育馆能否按时完工的担忧。

造句：Boo Radley's strange behavior and his life in social isolation fuel rumors among the neighborhood.

The United States discovered those plans in October of 1962, setting off a fourteen-day standoff.

set off

1. to make something start happening, especially when you do not intend to do so

  引起，激发〔尤指意外事件〕:

  News that the claims might be true set off widespread panic.

这种说法可能属实的消息引起了普遍的恐慌。

  Hong Kong's stock market fell, setting off a global financial crisis.

  香港股市下跌引发了一场全球性的金融危机。

2. to make an alarm start ringing 触响〔警报系统〕:

  Smoke from a cigarette will not normally set off a smoke alarm.

  香烟的烟雾一般不会触发烟雾警报器。

3. set sth  off, to make a bomb explode, or cause an explosion

  使〔炸弹等〕爆炸; 引发〔爆炸〕:

  Any movement could have set off the bomb. 任何动静都可能引爆这颗炸弹。

除此之外，set off 还有简单的“出发、启程”和“衬托某物”的意思

standoff

a situation in which neither of two opposing groups or forces will make a move until the other one does something, so nothing can happen until one of them gives way. 僵持

 There is no sign of an end to the stand-off between Mohawk Indians and the Quebec provincial police...

 The State Department was warning that this could lead to another diplomatic stand-off.

U.S. ships imposed a naval quarantine around the island, and Kennedy demanded the destruction of the missile sites.

impose

1. [T] if someone in authority imposes a rule, punishment, tax etc, they force people to accept it  强制推行; 强制实行:

  The court can impose a fine. 法庭可以强制执行罚款。

  impose sth on sth / sb

  The government imposed a ban on the sale of ivory. 政府禁止出售象牙。

2. [T] to force someone to have the same ideas, beliefs etc as you

  将〔想法、信仰等〕强加于〔某人〕:

  impose sth on sb

造句：No one can impose his or her beliefs on others.

quarantine

1) N-UNCOUNT:  oft in/into n

If a person or animal is in quarantine, they are being kept separate from other people or animals for a set period of time, usually because they have or may have a disease.

 She was sent home to Oxford and put in quarantine...

 No mammals other than people may enter the country without lengthy quarantine.

2) VERB:  usu passive

If people or animals are quarantined, they are stopped from having contact with other people or animals. If a place is quarantined, people and animals are prevented from entering or leaving it.

用表示检疫隔离的词来形容海军隔离，强调了隔离的严重性。

Following the events of 1961–62, economic and diplomatic isolation became the major prongs of U.S. policy toward Cuba.

prong

1. a thin sharp point of something such as a fork that has several points

〔叉子等的〕尖头，尖齿:

  sticking out like the prongs of a garden fork 像园艺叉的叉齿一样伸出来

2. one of two or three ways of achieving something which are used at the same time

 〔双管齐下时的〕方面，〔兵分三路时的〕一路:

  [+ of ]

  the second prong of the attack 第二路进攻