Related Clues:

• "Could we get on with it?"
• "However ..."
• "Did you forget about me?"
• Sound before 'Your, um, fly is open'
• Alternative to 'psst'
• "___ no-o-o . . ."
• Excuse maker's word
• With 57-Down, possible response to 20-, 31- or 39-Across
• ''Sorry to interrupt . . .''
• ''Um, excuse me . . .''
• Audible nudge
• Subtle warning sound
• 'However ...'
• "Could I interject?"
• Attention-getting noise