Think of it as meaning "of", except you put it on the other side of the word. This is basically true in English as well - "Joe's cat" is a cat of Joe. Note that "his" and "Joe's" are interchangeable here - in Chinese you use 的 in both cases. 杨老师的猫 - Teacher Yang's Cat 我的猫 - My cat 那只猫是我的 - That cat is mine (that cat is of me) 小小的猫 - tiny cat --- The characteristic OF the cat is that it is tiny. ^in this case you don't necessarily always need the 的 - ie 小猫 still means little cat. But it is very often like that. 他是从中国来的 - He is from China - [He] [is] [from] [China] [came] [of] In this case I believe the 的 is saying that "from China" is a characteristic of "him". Similarly 他是中国的 is effectively saying "he is of China". It also shows up in a ton of different places, in which case its better to just learn the full word it is a part of (or its being used in a less common grammatical sense). 有的 - some of, some 真的 - really 的话 - if, in the case of (你很冷的话 = if you are cold)

1 it's a part of an adjective 2 it shows possession like " 's " or "of" 3 it makes descriptive part of a sentence