I've learned English for years,but I still can't understand the English movies very well.I'm alway confused by those slangs and idioms. I learned a lot slangs from the dictionary, but I found that many of them even unknown by the native speakers.So I wonder if it's worth taking time to learn slangs.
I appreciate your answer.By the way, could u recommend some good English learning materials to me? I want it "NATIVE"

While some is common, different parts of American have some different slang terms.

Best a person can probably do it just ask about it when they hear one they don't understand.

Edit: This is neat, just put a word or meaning in the box and his search : )
http://www.alphadictionary.com/slang/

I give up learning slangs a long time ago. I found out that it is better for me to learn slangs that people actually use, that way when I talk to some one, they will know what I am talking about.
My suggestion for you if you would like to further educate yourself in the English language, get the basic grammar and sentence structure first. I learn english better this way.
You could go to a book store and get some basic english language books, learn all the adjectives, verb, noun and all those good stuff. In the end it will help you get a better job, because when companies hire some one, they prefer to hire some one who speaks english well without having to use slangs, since it will make you sounds professional.

Do yourself a favor speak English not slang...There will never be enough time to teach you all the slang Americans use..I appreciate someone who can speak a proper sentence without slang..and I am an American

If you want to learn English slang and idioms use this site,

http://www.urbandictionary.com

When you don't understand something just type it in there, it will give you the various definitions and meanings, sometimes slang words mean more than one thing.

this depends on where you're from....geographically..

all slang is not the same! in some places,words are different.

U can say 1 think in,say,one state,and it will mean something

else in,say,another.