OPPORTUNITY
Opportunity is an auspicious state of affairs or a suitable time:
Opportunity 是壹種有利的狀態或合適的時機：
“He would . . . trust to time and opportunity for the gratification of his revenge” (Frederick Marryat).
“他將…坐等時機來成全他的報復行動” （弗瑞德·莫亞特）。
“If you prepare yourself . . . you will be able to grasp opportunity for broader experience when it appears” (Eleanor Roosevelt).
“如果妳有所準備…壹旦機會出現，妳就會抓住獲得更豐富經歷的機會。” （埃利諾·瑞賽爾特）。
OCCASION:
Occasion suggests the proper time for action:
Occasion 暗含作某項行動的適宜時間：
“Who would do ill ne'er wants [lacks] occasion” (George Herbert).
“幹蠢事的人想要〔缺少〕 時機” （喬治·哈伯特）。
I seized the occasion to set the record straight.
CHANCE
Chance 常意味著因為運氣或偶然而出現的機遇：
This is a chance for the two of you to get acquainted.
這是壹次妳們兩個互相熟悉的機會。
Don't throw this chance away; it won't come around again. A break is an often sudden piece of luck, especially good luck:
不要讓這個機會溜走；否則它是不會再來的。 Break 經常是壹突然而至的運氣， 尤其是好運氣：
When the star was taken ill, the understudy finally got her first big break.
當主角生病時，替補終於得到了第壹次大好機會。
“The best you get is an even break” (Franklin P. Adams).
“妳最多能有壹次公平的好運氣” （富蘭克林P·亞當斯）
p.s 韋氏字典對chance 的解釋：
chance is the most general term and may imply determination by irrational, uncontrollable forces <e.g. left things to chance> or degree of probability <e.g. a chance of one in ten>
p.s. 具體解釋
occasion: n.場合, 時機, 機會
1、An event or a happening; an incident.
場合：重大的事件；事故
2、The time at which an event occurs.
這種事件發生的時刻
3、A significant event.
重要的事件
4、A favorable or appropriate time or juncture; an opportunity.
機會，時機：壹個有利的或合適的時間或時機，在這個意義上， 它是opportunity的同義詞
5、Something that brings on or precipitates an action, a condition, or an event, especially the immediate cause.
誘因：使促成或加速行動、狀況或事件進程的事物
6、omething that provides a reason or justification; a ground.
理由：提供理由或口實的事物；依據
7、A need created by a particular circumstance:
需要：壹種由特定環境而引起的需要：
“He must buy what he has little occasion for”(Laurence Sterne)
8、“他必須買他不太需要的東西”(勞倫斯·斯特內)
9、A large or important social gathering.
盛大場面：壹個大型或重要的社會集會
opportunity:
1、A favorable or advantageous circumstance or combination of circumstances.
有利的環境：適宜或有利的環境或多種因素
2、A favorable or suitable occasion or time.
有利的機會：合適或有利的機會或時間
3、A chance for progress or advancement.
良機：有利於進步或發展的機會
chance:
The unknown and unpredictable element in happenings that seems to have no assignable cause.
偶然性：在似乎無因可查的事件中末知和不可預測的成分
A force assumed to cause events that cannot be foreseen or controlled; luck:
機緣，僥幸：被認為引起不能預知或控制的事件的力量；運氣：
Chance will determine the outcome.
機緣將決定結果
Often chances The likelihood of something happening; possibility or probability:
常作 chances 或然率，機率：很有可能發生的情況；可能性或極可能性：
Chances are good that you will win. Is there any chance of rain?
極有可能妳會贏。有可能下雨嗎?
An accidental or unpredictable event.
偶然的事，意想不到的事
A favorable set of circumstances; an opportunity:
機遇，機會：
a chance to escape.
逃跑的機會
A risk or hazard; a gamble:
冒險，無把握的事：
took a chance that the ice would hold me.
甘冒冰層可以承受住我的危險
Games A raffle or lottery ticket.
遊戲 獎券，彩票
Baseball An opportunity to make a putout or an assist that counts as an error if unsuccessful.
棒球 刺殺出局，夾殺：做壹次傳殺或助殺的機會，不成功則算誤殺
adj.（形容詞）
Caused by or ascribable to chance; unexpected, random, or casual:
恰巧的，偶然的：由機緣引起的或歸因於機緣的；沒有預想到的，隨意的，隨便的：
a chance encounter; a chance result.
邂逅；不曾料想的結果
v.（動詞）
chanced， chanc.ing， chanc.es
v.intr.（不及物動詞）
To come about by chance; occur:
偶然發生，出現：
It chanced that the train was late that day.
那天偶然火車晚點
v.tr.（及物動詞）
To take the risk or hazard of:
冒…險：
not willing to chance it.
不願意去冒險