Well, when I have a conversation, I always get stuck with some words. For example, when I want to explain something that has been happened to me in the past, and some words and abbreviations like: I've and ain't and especially I'd. 

If anyone can help me. I'd appreciate it.

<em>This page is a really good reference:</em>

<em>http://grammar.about.com/od/words/a/EnglishContractions.htm</em>