Thanks fireflytech for pointing that out. It's true that I'm looking from a native speaker's persepective, thus it might not be very clear or goes with a learning concept. Anyway i just want to add on a little bit further =) Run vs Ran In english, we have different forms of a word to show past tense, past present tense etc. However in chinese, 跑 is just 跑, what we can do to show it as 'I ran', is to say it in another way with the same meaning - 'I finished running.' I run - 我跑 I run along the path - 我沿着路跑 I ran - direct translate should be 跑了, but limited ways we can use it. I ran for 40kilometers. 我跑了40公里 The more common one that we're looking for is: I ran - (change to) I finished running - 我跑完了 I've （already) ran - i've finished running already 我已经跑完了 (eg answering to your coach when asked whether u've ran?) fireflytech pointed out an interesting fact: the usage with 过 你吃过饺子吗？- have you ever eaten dumplings? However, whole sentence do change if u add another '了‘ 你吃过饺子了吗？ Have you eaten dumplings already? (eg mum cooked a plate of dumplings for you, after a while she checks on you, asking you whether u've eaten them already?' If you're asking someone whether they eaten their meals. 你用过餐了吗？ more polite way 你吃过了吗？common way When answering: 用过了 I had my meal 吃过了 I've eaten Or a more common/friender way people ask: 吃饱了吗? "Have you eaten (very full) already?" 吃饱了 "Eaten. (very full :P)" 过: like fireflytech said, it's like 'ever' 了: a combination word to show something you did has become 'past' 吃 - 吃了, 去 - 去了 etc. ...过了...: somehow like... 'been/finished'?, mostly use for question and answer. Eaten already? 吃过了吗？Eaten. 吃过了。 Present tense is '正在' 我正在吃(东西) I am now eating (something) Good luck to your learning, I'm sure you'll get use to them when you see more/listen more, you'll get the natural flow once you're familiar with it. =)