how can you tell when a person is telling a lie?

There are many good liers and sometimes you can't understand when somebody is lying or not. BUt normally you can see it in the eyes of somebody. Life can teach you how to do it. The more people have lied you the better you would understand it. So life is the greates teacher for the different situations.

I am not sure how to explain this but I just know. I can tell how they look at me the way they answer and just in general their actions and body movements...

I'm pretty gullible, so if one's a good liar, then I can't tell. My husband is very good in telling, he's very analytical, and I get surprised sometimes that I didn't think about what he thougt. I myself is not a good liar that's why I rather omit than change the facts, you know what I mean. I don't believe though that you can tell when they can't look straight in your eyes, maybe kids does this. But grown ups, some are just excellent in lying.

when that person can't look straight in your eyes.. and that he or she commits so many excuses to hide something..