Related Clues:

• Keep mum after green light produced surprise!
• "Hmm, I didn't know that!"
• Head scratcher's remark
• "No kidding"
• "I don't know" lead-in
• "Gee whiz"
• Crikey!
• Turn signal, on a horse
• "___-whiz!"
• Surprised expression
• 'No kiddin'!'
• "Who knew?"
• 'Didn't know that!'
• Haw's mate
• 'Oh my goodness!'