Possible Clues:

• 'What'll ___?' (waiter's words)
• "Let __": Beatles hit
• The Beatles' 'Let --'
• ''How hard can __ ?''
• "Let ___ known ..."
• "Could __ Magic": Barry Manilow hit
• 'Let -- Me'
• Barry Manilow's 'Could ___ Magic'
• 'What'll ___?' (bartender's question)