Possible Clues:

• Analogist's words
• 'That -- say ...'
• Lenin's 'What ___ Be Done?'
• Part of a proportional representation?
• 'That's all there -- it!'
• SAT analogy words
• Words in a ratio
• "This __ certify ..."
• ''To know me __ love me''
• "To know me ___ love me"