Delphine loves to know whether things are real or pretend, so after a lengthy discussion about ghosts (starting with "what do ghosts eat?") she changed the subject:
"Are dinosaurs real?"
"Not any more. They're all dead."
"Why are they all dead?"
"Well, that's a good question." (The lovely thing about having children is that you can occasionally answer questions with that without meaning "I don't know.") I then took a big breath, about to explain the asteroid theory (because who doesn't love the idea of a flaming rock flying at us from space?) when Delphine advanced her own theory.
"Maybe they're all dead because people took the bones out of them to put in museums."
Well, I can't say I'd thought of that.