表现，to show 行为，a behavior

“表现”是one person眼中对于“another person”的评价；“表现”反映的是一种结果，包括思想的，行为的结果在别人眼中的反应，但是“行为”只是对one person 而言；是单个个人的behavior，是objective。

表现：performance 行为：behavior

表现 is more like "performance" in english,generally it was used as a nom,while 行为 is more close to the the word"behavior",it can be used both as a verb and a nom.

表现biǎo xiàn 1.to show; to display; to exhibit; to represent; to express; to manifest 2.to behave; to perform 3.an expression; representation; manifestation; behaviour 行为xíng wéi 1.behavior; conduct; bearing; comportment 2.acts; actions; deeds; doings; proceedings