We stayed with friends for a few days on/in PEI. They just returned from a visit to Quebec City; Friend Stef showed Henry the photos she took at the big aquarium.
Stef: Do you know what this is?
Henry: (scrutinizing a fuzzy picture) No.
Stef: It's a jellyfish.
Henry: (nodding in recognition) Oh, yeah!
Stef: Do you know what a jellyfish is?
Henry: It's an invertebrate with stinging tentacles.
Stef: (mouth agape) You know what an invertebrate is?
Henry: Yes. A creature with no backbone.
Stef: (mouth agape) !
This is the same boy who stares at me as if I am speaking Latin when I ask him to clean up his Lego.