(二)act大都指短暫的、簡單的動作;action 指較長的、複雜的行為。例如我們應該說the action of a machine，而不說the act of a machine。
(三)在下列場合，只能用act，不能用action;the act of cruelty，folly，mercy，God(天災)，jumping，stealing，walking，kindness，madness...。
(四)在下列場合，只能用action，不能用act:to take action，in speech and action，a man of action, put into action, ready for action, to come (bring) into action...。在某些習語和表示“作用” 的涵義時，也只能用action，不用act。例:Actions speak louder than words;Chemical action(化學 作用);capillary action(毛細管作用);the action of light (heat)(光/熱的作用)……。
下面例句說明act和action的分野:
The pickpocket was caught in the act. 扒手在行竊是被抓住了。
Trying to cover up the mistake is an act of folly. 試圖隱藏錯誤是一件愚蠢的事。
In the act of picking up the ball, he slipped and fell. 他在拾球的時候滑倒了。
Don"t take any action. 不要採用任何行動。
He is a man of action. 他是一個很活躍的人。
The government must take action to prevent unemployment from deteriorating.
政府必須採用行動防止失業情況惡化。
有時候，act和action之間的界限並不是很清楚的，例如在下列句中，它們可互換使用:
It was an act (or action) that they were to regret bitterly.
Her heroic act (or action) will be long remembered.
You will be judged by your acts (or actions).
最後還需補充一點，在指某個行為或行動的特徵時，應用act，不用action。例如:an act of thoughtfulness; the act of a fool，但是，在該行為或動作之前如有形容詞修飾時，則改用action，不 用act。例如我們說:the act of a careless person; I don"t like his careless action.
act用作名詞，很易與另一名詞action混淆不清。請注意，它們之間有如下 的區別:
(一)一般說來，act指個別具體的行動;action 指抽象的行為。
(二)act大都指短暫的、簡單的動作;action 指較長的、複雜的行為。例如我們應該說the action of a machine，而不說the act of a machine。
(三)在下列場合，只能用act，不能用action;the act of cruelty，folly，mercy，God(天災)，jumping，stealing，walking，kindness，madness...。
(四)在下列場合，只能用action，不能用act:to take action，in speech and action，a man of action, put into action, ready for action, to come (bring) into action...。在某些習語和表示“作用” 的涵義時，也只能用action，不用act。例:Actions speak louder than words;Chemical action(化學 作用);capillary action(毛細管作用);the action of light (heat)(光/熱的作用)……。
下面例句說明act和action的分野:
The pickpocket was caught in the act. 扒手在行竊是被抓住了。
Trying to cover up the mistake is an act of folly. 試圖隱藏錯誤是一件愚蠢的事。
In the act of picking up the ball, he slipped and fell. 他在拾球的時候滑倒了。
Don"t take any action. 不要採用任何行動。
He is a man of action. 他是一個很活躍的人。
The government must take action to prevent unemployment from deteriorating.
政府必須採用行動防止失業情況惡化。
有時候，act和action之間的界限並不是很清楚的，例如在下列句中，它們可互換使用:
It was an act (or action) that they were to regret bitterly.
Her heroic act (or action) will be long remembered.
You will be judged by your acts (or actions).
最後還需補充一點，在指某個行為或行動的特徵時，應用act，不用action。例如:an act of thoughtfulness; the act of a fool，但是，在該行為或動作之前如有形容詞修飾時，則改用action，不 用act。例如我們說:the act of a careless person; I don"t like his careless action.