Why is a lesson two hours?

La Guardia is a good school, particularly for ESL students. The teachers are experienced at teaching and struggle to teach very good English for students. However, I am not sure whether they know it or not, but a lesson should not be two hours. During the two hours just sitting and listening to the teacher and sometimes it can be boring.
Sometimes the students come to school a little sleppy and they do not want to remain in class two hours because after the first hour, they think only about the break and resting. This is not good for our concentration.
I think that the school administration shoul find a way out and they should debate this sitiuation. They should take of students opinions. I think two hours are so much; maybe there can be ten minutes a break after the one hour.