Historical clue formulations

• "Go ahead!" — 2018-12-23
• "I can only ___ much" — 2015-06-04
• "One can only ___ much" — 2013-03-17
• "I ___ appreciate ..." — 2008-04-06
• "I can only ___ much" — 2007-12-25
• "I can only ___ much" — 2005-02-11