了 is not past tense ... it is completed action ... Use after a verb or adjective, expression movement or change already complete. 今天下雪了(today it snowed and it finished snowing . 读了两遍 (read twice) 他已学了两年 中文(this means he studied (but no longer ) chinese for 2 years ) can be used at the end of sentence or in the middle if expressing a pause in speech .... 好了， 别再提那件事了。(Okay, don't talk about it again.) 天一下雨， 我就不出门了。(I don't go out when it rains.) there is change new situation 刮风了（windy）

Good Morning, Jenna, it is 8.30am in my part of the globe :) What time is your watch indicating? It is very similar to the English word 'already', which appears naturally whenever we write or speak. When ‘了’ is joined with another Chinese character, it could mean totally different thing. e.g. 了解 means understand. 了解了means understood. An example; "有时，情侣会因为太了解了而分开。 Sometimes, a couple may break up despite knowing each other thoroughly." Here the character 了 represents 2 different meaning. Don't worry too much over any particular character, because there are 3000 commonly used Chinese characters like this and more than 40000 in total. Just enjoy the process of learning as you converse with Mandarin speaking friends :D

Firstly, 了is a kind of modal particle in Chinese, and it doesn't have any practicle meaning. 了 is usually used in daily conversation, after the verb and adjective, and it's informal. When you use了, it gives people a sense of friendliness and makes others feel amiable. You can use 了 in your daily life when communicating with your families and friends. However, you'd better not use了 in a formal occasion, otherwise it will make others feel that you are not a bit serious. That's my answer, and I hope it helps.

Mostly we use verb+了 to express pp. form of verb. If you use verb+ n., you could use it either before n. or after n., like 我吃饭了 or 我吃了饭 And if 了 appears in the end of sentence and no verb just before it, it will be used as modal particle. Like 这些事都是过去的了， we could also say 这些事都是过去的啦

That dastardly 了. I hope you never have to be as a bad at using 了as me. I think for future reference when you're studying etc, you can search 'allsetlearning chinese grammar', then you just choose the different types of 了 you want to learn about, they do it in terms of complexity so the short easy 了 uses are labelled A(1)/(2).... That website is also great for other grammar uses and the best is yet to come, you can search by textbooks!!! How beautiful.