- the penny has dropped
- the penny dropped
- Understanding is reached, one comprehends.
- The penny drops as Fred realises he has been conned.
- 2011 August 27 (broadcast date), Doctor Who, series 6, episode 8, Let's Kill Hitler:
- AMY: In the time I've known you, when have you shown the slightest interest in a girl?
- MELS: Penny in the air!
- AMY: I've known you for, what, 10 years? I've seen you practically every day. Name one girl you've paid the slightest bit of attention to? (RORY is flustered, runs from the room.)
- AMY: Oh my God! Rory! (AMY runs after RORY.)
- MELS: And the penny drops!
understanding is reached, one comprehends