Possible Clues:

• Skeptical response
• Soldiers stopping homeless person getting a lift? Come off it!
• 'Yeah, sure!'
• 'Yeah, like you have a chance!'
• 'Ain't gonna happen'
• "No chance of that happening!"
• 'Like that'll ever happen'
• "What you propose is not going to happen!"
• 'Oh sure, that'll totally happen!'
• "You could never!"