过 normally need follow to a verb, for example, 吃过，看过，去过etc, and it indicates that the action happened in the past and have completed; whereas 了is used in the end of the sentence, and make the response sound gentle. and also sometimes u can use them in the same way, such as 你吃过吗？= 你吃了吗。 the best way is chat with Chinese people, and then with the exercise going on, u will be familiar with their usage. keep practising!

举几个例子: 你吃了吗 我刚吃过了 你看那部电影了吗 我还没看过 你听说过他吗 没听说过

了 = completion of an action, either in the future or in the past 过 = indicates that it happened in the past and it can be used to emphasize past experience If you want to read more about it: http://chinese.rutgers.edu/class_content_simplified_chinese/level1/class30-to-39/class32/aux2_cs.htm Good luck! 祝你好运!

no relationship between these two words.