You guys probably didn't know this, but when Chelsea Dagger was a little boy, her dearest dream was to one day become a famous t-shirt screen-printer. Well, that or a dinosaur, but the latter proved too difficult to accomplish, so she turned her considerable talents to fashion design and launched a fabulously unprofitable company that involved her scrawling words onto cheap cotton shirts with a mechanical pencil. News of her entirely undeserved and mostly imagined fame soon reached the wizarding world, and next thing you know, the Chosen One himself, Harry Freakin' Potter, was knockin' on Chelsea's door and asking for custom-made v-necks for himself and his two best friends, Ron "Shazam!" Weasley and Hermione "Boom It To The MAX" Granger. Now, the Dags isn't about to just hand out her 25-cent merchandise for free, so she agreed to make the shirts on one condition: the gang has to solve a riddle first. BET YOU CAN GUESS WHERE THIS IS GOING.

If you're familiar with the Identifying Sentence Error questions in the SAT Writing section, then you know that lurking among the verb tense errors and pronoun agreement mishaps are these sneaky little things called idioms. Idioms are quirky grammatical constructions that are intended to be taken figuratively. Each language has its own collection of idioms, and most people are so used to hearing them that they never think about them. For example, it would be correct to say "I live on this street." There's no specific rule explaining why we say we live "on" a street rather than "in" a street. But saying "I live in this street" is dead wrong (and it would cost you points on the test).