Sleeping in class

I think that sleeping in classroom is not good. Fir teacher and who pay us school it's a affront, a injury.

when u dont want to pay any attention to the study which is going in the class

There could be a number of reasons. Maybe they didn't eat a proper breakfast, in which case their energy would be low. Maybe they didn't sleep too well the night before, or had a late night and didn't get enough sleep. Maybe it's too warm in class, and the air stale.. nothing to invigorate you. Maybe the teacher is just plain boring or the pupil doesn't care if the teacher is boring because they don't wanna learn!

whenever we r in class that to when teacher starts lesson we will sleep its commom thing and not only that when we start reading our text books we will gey sleep but when we r readinga novel we wont.I too dont know the reason.May be psychological feeling

Because they are tired and didn't get enough sleep the night before.

because they arent getting any sleeep at night