I know that in MLA format a parenthetical citation has to come right after the quote and before the period, but WHY?

2 answers

I'm not sure why!

I've always figured it is because the citation is needed with the quotation and therefore both are part of the same sentence. The period comes AT the end of the sentence.
What is the simple subject and the simple predicate of the following statement: Where did you get that ice cream?