Possible Clues:

• Summons on an essay
• Question from someone waving across a crowded room
• Words on an F paper, maybe
• Ominous note from a teacher
• Teacher's note accompanying a bad grade, maybe
• F words?
• Note from a teacher (... first 2)
• Ominous request on a graded paper
• Worrisome directive from a boss
• Ominous note from the teacher