what's the difference between "despite of " and "irrespective of "?

안녕、안녕하세요、안녕하십니까、여보세요这几句话怎么用？

“AA制”这个词只是在中文出现么？英语呢？

how to use the word "biweekly" it has both the meaning of "twice every week" and "once every two weeks", isn;t this conflict and confusing? How can i know which meaning it is?

AmE & BrE there are so many differences between American English and British English, some of which make no difference in understanding yet some could be quite confusing.  Wanna  collect  as many examples as possible ?

Is it correct to say "my pleasure to help if you're ever in need" ?

First notebook entry: Introducing myself Hey, guys from all over the world ! I'm a Chinese girl with a complicated characteristics .Sometimes i may be very outgoing and talkative and have no problems communicating with all sorts of people, yet , sometimes i can be extreamly silent like a lonewolf who know little about social things... I love multicultural things and have great passion for foreign languages .Now i'm learning English and Korean and hope to make friends with who speak these languages and learn from each other...