The older students are off on a school trip leaving Akari and a needy Chinatsu alone.  Nadeshiko watches Himawari and Sakurako fight and remembers them as 
children.
Why are you talking about that?
¿Por qué estás hablando de eso?
¿No tenéis otro tema de conversación mejor?
Por que vocês estão perdendo 
tempo com besteira?