"Oh," says Chie. Then, after a moment, "Yeah, I think that's what post-apocalyptic is. Places that had a big disaster in the past like that. A college is a place you go to study at... which I guess can be in a walled city. And, uh, yeah, I guess I have been to another world if you count the TV world. Which we called because we got there by stepping into TVs. Uh, do you know what TVs are?"

Because it occurs to her that maybe he doesn't. Poor kid looks like he'd been starving at some point and if his family couldn't afford food they probably couldn't afford a TV either.