Be aware that cause/'cos is slang, and so you should try to avoid it. Some basic contractions: It's/(It is/It has) They're/They are We're/We are He's/(He is/He has) http://grammar.about.com/od/words/a/EnglishContractions.htm Some others: Someone/Somebody Anyone/Anybody No one/Nobody Everyone/Everybody Therefore/So* Also/too* What time/when Why/(What...for/For what) - The order and word placement depends on the sentence Why/For what reason - Only if you want to sound fancy Below/Beneath/Underneath/Under Among/Amongst Amid/Amidst Once/One time Twice/Two times Thrice/Three times But/however/though/yet*/although/ Besides/Except (for) Beside/Next to In addition/furthermore Until/('til/til/till) Because/since*/As a result (of) - The latter is only applicable some of the time. Consequentially/As a result, Another/An other - The former is convention, even though it really should be two words. (A/An)/One* * - Can mean something else, in certain contexts.