User:Necrohol

Hai.

then and than
Despite their pronunciations being very similar, they are different in meaning.

then is used in one of the three following cases:

1. at that time; at the time in question
 * e.g.
 * I was living in Cairo then.

2. after that; next; afterward
 * e.g.
 * She won the first and then the second game.

3. in that case; therefore
 * e.g.
 *  If you do what I tell you, then there's nothing to worry about. 
 *  Well, that's okay, then.

Whereas than is used in either introducing the second element in a sentence (He was much smaller than his son.) or in expressions introducing exceptions or contrasts (He claims not to own anything other than his home.).

its and it's
Yet another common error is its and it's.

Its is a possessive adjective, meaning it describes an object or anything that associates with an item and/or animal.
 * e.g.
 * He chose this area for its atmosphere

On the other hand, it's is a shortcut for it is. Self explanatory here, folks. Ehh, I'll provide an example anyway.
 * e.g.
 * it is - It's my fault.
 * it has - It's been a hot day.

their and there
Yeah, an extremely common error.

Their is possessive, referring to an object(s) belonging to a certain number of people.
 * e.g.
 * The ball is their property.

There is an adverb, referring to a certain position or area.
 * e.g.
 * We went on to Paris and stayed there eleven days.

Note: they're can also be confused with their and there, although they're is quite uncommon. They're is a shortcut for they are and they were, depending on how the sentence is constructed.

should of and should have
This one really pisses me off.

SHOULD OF DOES NOT MAKE ANY SENSE AT ALL. Seriously, I have no idea how anyone has the gall to use should of.