ぼくにはなにがどう違うかわからないので、二人の会話を聞きながら「へー」とか「ほー」とか言うだけでした(笑)
早苗さんとナズのひとにはナイショだぞ!

I'm not sure what was different about it, so all I said while I listened to them talk was "Wow" and "Really?" :-) Don't tell Sanae-san or the Naz person!