Possible Clues:

• 'You ___ lying!'
• 'I bought some batteries, but they ___ included' (Steven Wright)
• "If you __ you, then we'd all be a bit less we": wisdom from Piglet
• ''As if that __ enough . . .''
• “You ___ kidding!”
• 'As if that ___ enough . . .'
• Cole Porter's '___ We Fools?'