Secondly I'm not sure that even if the teacher is experienced he can teach 45 students in one classroom. We usually devide more than 25 students into two or three groups. You ask how you can improve your English. Keep on listening to English programs on TV and on the radio too. Don't worry if you don't understand everything. Just listen and try to immitate them when you teach at school, I mean the pronunciation. In two or three months you'll feel that you understand most of the things they say. You can also find someone and speak Endlish to him. And finally listen to English songs when you have nothing to do. Good luck! I know you are a good teacher. If not you'll be one very soon.