This is a quiz which will test your knowledge on the appropriate use of there, their or they're.  Remember "there" shows location, if you drop the "T" it spells "here" and this should help with remembering the definition.  The word their shows ownership; if you drop the "t" it spells "heir" which means someone who inherits something.  The word they're is a contraction word which means it can be split into two words, "they" and "are." If you can seperate the words and your sentence makes sense then more than likely it is the appropriate use of they're.