“友好的行为”常见的英文表达是 friendly behavior 或 friendly act。
friendly behavior：更侧重于描述一种持续或一般性的友好举动方式。例如：His friendly behavior towards others won him many friends.（他对别人友好的行为为他赢得了许多朋友。 ）
friendly act：通常指某个具体的友好行动。例如：That was a very friendly act you did for your neighbor.（你为邻居做的那件事非常友好。 ）