「願望只是美麗的彩虹，行動才是澆灌果實的雨水。」（英國諺語）。「行動是知識成熟後的果實」（R. B. Fuller）。英國散文家培根認為：「人生的目標不是知識而是行動」（“The great end of life is not knowledge but action.” – Francis Bacon）。可見行動的重要性。
Action speaks louder than words（行動比言語更響亮，事實勝於雄辯）：What a person actually does means more than what he says.（我們判斷一個人，要看他怎樣做，而不光是聽他說甚麼。）
美國前總統傑佛遜強調：行動可以刻劃和界定一個人的性格。（“Do you want to know who you are? Don’t ask. Act! Action will delineate and define you.” – Thomas Jefferson）
Act
Act，一般解作行動，又可以解作行為：an act of kindness（善意的行為）；法令：Act of Parliament（議院通過的法案）；an act is also one of several pieces of entertainment in a show or one act of a play（表演節目的一段，或一齣戲其中的一幕）。
An act of God 指不可控制的自然現象，不可抗拒的天災，例如風暴、洪水、地震。
幾個值得留意的 idiomatic expressions of “act”：
a tough act to follow（令人望塵莫及的人）：a person who is so successful at something that it will be difficult for anyone else coming after him to be as good：也可以說：a hard act to follow（前人做得太好，後來者不容易超越）。
a juggling act 表示同時要應付兩個或以上重要的工作或活動，例如有職業的母親，既要工作，又要照顧孩子，還得做家務：a housewife managing her home life and work was proving to be something of a juggling act.
A balancing act is trying to treat two things equally. 讓想法相反或互不接納對方的人，都感到滿意，很不容易：The UN must perform a delicate balancing act between the different sides involved in the conflict. It is a process or performance trying to please two or more groups who want different things.
get in on the act（參與，插手），例如：別人先開始做，自已為了得到好處而加入，跟着去做：You become involved in an activity that somebody else has started and after it has become successful because you want to get something out of it for yourself.
get your act together（集中精神，組織起來）：organize your activities in a more effective way in order to achieve something（有條有理地籌劃，按部就班地做事，希望取得更大的成功）。
Act 作為動詞：To act is to take action and make a move. Act as a verb is often followed by an adverb relating to speed or urgency: he acted at once/immediately/promptly/quickly/swiftly.
If you want someone to behave in an adult manner, you can say: act your age（舉止要似一個大人）that means you have to behave more maturely; acting the fool（逗人笑）is playing around and not taking things seriously and behaving in a foolish manner; act a part（裝腔作勢）is to hide one’s real feelings.
Action
Action 可以指行動，也可以指動作；put into action（執行，實行）。Action is the process of doing something in order to achieve a particular thing. 例句：Each of us must take responsibility for our actions. Firefighters took action immediately to stop the blaze from spreading. What is the best course of action in the circumstances? You follow a course of action means you act in a particular way.
Act or Action 用法的區別
Act 強調所做的事，常指片刻或短時間內所做的事；action 強調做事的過程，可以包含多項在短時間內所做的事。具體、簡易和短時間的行動或動作，通常用 act 來表示；抽象、持續和複雜的行動或動作，則應該用 action 來表達。
Act and action have the same meaning but are used in different patterns: act is usually followed by “of” and used with an adjective. Action is not usually used with “of” but is usually used with “his”, “her”, etc., such as a heroic act of bravery: his heroic actions during the war. Action often combines with “take” but act does not。
再多舉數個 action 常用語的例子：
take action（採取行動）：you take tough/firm/decisive/drastic action; you put your ideas into action; in action（實施、運作、積極從事某活動）：I like to see the new computer system in action; a slice of action（插手，參與）：an opportunity or a role in an interesting or exciting activity, especially to make money（尤其是為了賺錢，或獲得其他好處而參加活動） ：Foreign companies will all want a slice of action if the new airport goes ahead.
最後，action 有時也可以指訴訟：to bring a legal action against somebody.
