50%
Complete the senior wizard's rather stern note to his new, accident-prone apprentice. Select the grammatically correct option for each gap.
"_________________________ accidentally turn the headmaster's cat into a teapot again, please consult chapter four of the manual immediately. Furthermore, _______________________________ my previous warning about the fireball spell, your left eyebrow would still be intact today."
Should you
This is an inverted first conditional. It means "If you should turn..." or "If you turn...". We know it must be "Should" because the verb "turn" is in the base form. "Had you" would require the past participle ("turned"), and "Were you" would require an infinitive ("to turn").
had you not ignored
This is an inverted third conditional functioning inside a mixed conditional sentence (past action, present result). It means "If you had not ignored..." We know it refers to the past because the eyebrow is already gone, making the condition a past regret!