What class and grade does Itsuki teach?

For those who have seen the honeymoon arc, there are a few moments we see Itsuki in a school building doing some work on the computer. However, it's never stated what grade she teaches. Another thing is that while the girls were helping Lily, Itsuki states that she doesn't teach English. If she doesn't teach English, what do you think she teaches? I don't recall her saying anything in the two seasons or movie or the ovas about exactly what kind of teacher she wanted to be but then again it's been a while since I last watched if I'm being honest so I could be forgetting something. I'm pretty sure she teaches high school mainly because of how rude and strict her boss was. And since she liked Science so much my guess is she's a Science teacher for high school, but what do you think?