Help the exhausted Resident Advisor complete the new dorm rules poster.

Under no circumstances _____ the communal microwave to dry your wet socks, as it will inevitably summon the fire department again.

The correct answer is should you attempt to use.

Placing a negative restrictive adverbial phrase like "Under no circumstances" at the beginning of a sentence requires subject-auxiliary inversion. The modal auxiliary "should" must swap places with the subject "you". "Did you attempt to use" features correct inversion but the wrong tense, as it refers to the past rather than a general rule about future actions.