Top 8 most common misspoilings in the English language

[Galaki]

Final-Fan said:
If you say "I have a pen", you're talking about any old pen. If you say "I have the pen", there's a specific pen you mean, one that was probably already the subject of discussion.

Is that a pen in your pocket or is the pen just happy to see me?

Did I make any grammar or spelling mistake? :)