Historical clue formulations

• "I'm sleepy" signals — 2026-05-25
• Signs of exhaustion — 2023-11-14
• Can't keep one's mouth shut? — 2020-10-18
• They might precede "Well, we must be going" — 2019-02-19
• Expressions of boredom — 2018-05-28
• Reflexes said to be contagious — 2013-04-21
• Signs of boredom — 2011-07-04
• Is wide open, as a chasm — 2006-09-06
• Signs of boredom — 2005-09-20
• Shows signs of boredom — 1999-03-09
• Oscitates — 1994-08-26
• Signs of boredom — 1994-01-23