Verb conjugation of "beleidigen" in German

I will usually use the most usual sense of the term, and not the more sophisticated ones and I think you will understand what I wanted to say. In any case we should review all words every two days or so.
Productivity declines when it is too hot outside. Oscar therefore closed his laptop and production unit and headed towards the lake where his pretty girlfriend was waiting for him. Once he arrived he bought a ice cream as a surprise.
The course was a bit tough because the teacher always gave lots of homework. We were upset about his behaviour. He was very arrogant towards all the students. It was simply no fun to study there.