Gin-san takes history lessons, and teaches you how to hide your porn mags?
Tsukuyo tries to teach Seita history, the subject he's not great at. However, her training (?) methods end up leaving him scarred, which makes desperate Seita ask Gin-san to take over as his tutor...
but being gorillas, they started 
fighting over bananas or something,
لكن لأنّهم مجرّد غوريلات بدؤوا القتال على الموز وما شابه
pero como eran gorilas, 
empezaron a pelearse por bananas...
mas por serem gorilas, começaram 
a brigar por bananas ou coisa assim,