”了“有很多用法，通常在汉语课中，需要很多课时来解释”了“在不同情况下的不同用法。“了” is not only used in the past. 举几个例子： （1）The modal particle ”了“ This "了" is used at the end of a sentence, indicating the happening of something, the completion of an act or the emergence of a circumstance and the change of a situation. a. the happening of something: 他去公园了（还没回家）。 b. the completion of an act: 他上午去公园了，现在回家了。 c. the emergence of a circumstance:他突然摔倒了。 d: the change of a situation: 夏天来了，树叶绿了。 try to compare those two sentences: a: 你去哪儿？(Where are you going?) b: 你去哪儿了？(Where did you go?) （2）The situation of ”Verb + 了“：Usually there is one ”了“in a sentence, why are there sometimes two ”了“ in one sentence? a: If there is an object after "verb + 了", the number-classifier phrase or other word is required before the object. (a) 我买了一本书。（I bought a book） (b) 他吃了三个苹果。（He ate three apples） b. If the object does not have a number-classifier phrase or other attributes before it, "了" must be ALSO added at the end of the sentence to make the sentence complete. The function of such a sentence is to transmit certain information and draw the attention of the listener to a fact. (a) 我买了书了。（which means “you don't have to buy the book for me because I have bought the book already”） (b) 他吃了三个苹果了。（which means “He has eaten three apples, can't take more now”） Today I went to a cafe. - 今天我去咖啡店了。

地獄有18層 但是 教書先生 誤人子弟 將會下第19層 "了" 的用法 反反覆覆被中文學習者提問 很多中文母語人士 受了英文文法的毒害 都認為 "了" 就是表示 "過去"( things that were done in the past) 恕我直言 這也是 誤人子弟 的說法 中文無動詞變化 亦無時態變化 那又如何 會專門為了表達 "過去" 而創造 "了"呢 以下例句 是 以子之矛攻子之盾 "明年六月 我就畢業了" 既已明言 "明年六月" 還能強辭說是 "過去" 嗎 中文的 "了" 是表示 實現 (actulization / realization of an event or state) 用英語的語法概念 套用在 中文"了" 的學習上 只會讓自己更加疑惑

Dont care too much about the different meanings of 了, it's ok to remeber the normal use. also it's the way that i use to learn English.

It can be used to Describe something is done,or something,happened in the past Before a certain time point.

yes, it's shows simple past or confirms quality