Wow, tough crowd.Originally Posted by nutmeg
What about, the Cat Test? Prepositions are anything a cat can do. A cat can go up, go down, go over, go around, go under, go beside, go in, go on, go out, go to (the sofa), go for (some milk), go with (you), and so on.
Now, there are a few things that cats can't do. For example, cats can't go of, so you have to memorize the prepostion "of".
As for our example sentence, "Everyone except Todd left", we're dealing with an exception to the rule. except for is the standard phrase, it's a phrasal (two -word) preposition, and "for" is often omitted.
EX: Everyone except for Todd left.
Preposition: except (for)
Object of the preposition: Todd
Hope that helps.