It is a kind act (action). 这是一种和善的行为。
His heroic act (action) was long remembered. 他的英勇行为永久记在人们心中。
2)具体的、短暂的、简单的行为用act, 抽象的、继续的、复杂的行为用action。例如:
What we need is acts, not words. 我们要的是行动,不是空话。
Speech and action are different things. 空话和行动是两码事。
He was caught in the very act. 他当场被抓。
We should suit the action to the word. 我们要言行一致。
3)在下面两个固定搭配中,act 和 action 不可互换:
The thief was in the act of stealing. 这贼正在偷东西。
We must take action. 我们要采取行动。