While taking their usual bath, the boys discuss how much Kyotaro is like an old man. The next day, when they go to school, they find themselves exhausted by climbing up the stairs... and learn that they're all becoming old men!
Well, we worked up a sweat, 
so let's take a bath.
حسناً، تعرّقنا كثيراً، لذا لنستحمّ
Also dann …
Bueno, trabajamos mucho.
Démonos un baño.
Bueno, trabajamos mucho.
Démonos un baño.
Bref…
Bene. Dopo una bella sudata, 
ci vuole un bel bagno.
Bom, nos esforçamos e suamos,
 vamos tomar um banho.
Ладно, мы все порядком вспотели,
давайте-ка искупаемся.