1. ich glaube es heißt '' a musican/musicteacher''
2.''In the breaks i played on the piano sometimes, that was very cool.''
müsste imho auch falsch sein.Richtig währe doch '' Sometimes, I played in the break on the piano, and that was very cool.''
3. Ich glaube, es heißt'' We spended two days for stocktaking. We counted every instrument in the stock''
4. müsste es heißen '' At one day, there was [...]''

5. Irgendwie bin ich mit dem Satz nicht einverstanden.Ich glaub, da ist irgendwas nicht richtig.

''It was interesting but also sometimes boring, becouse many rookies tried to play an instrument, however, it was a terrible sound and sometimes i wished to throw them through the window .''