The mouse is so quiet that you can't hear it even as it scurries over the floor of a church, where everyone is silent in prayer.
I believe the paradigm that church mice are both poor AND quiet is well-established in Disney's (animated) Robin Hood film.
Quiz creator, fix this. Please.
The original (and complete) phrase was "happy as a clam at high tide".
Due to the obviously exhausting nature of saying that entire phrase, over the years, it has gotten truncated down to simply "happy as a clam".
then got it with poor. No biggie. Great quiz.