They always complained about the school's brooms: some of them started to vibrate if you flew too high, some always flew to the left, some just didn't fly.
I think there is a problem in this sentence. there should be "and" before "some just didn't fly ". The sentence will be :
They always complained about the school's brooms: some of them started to vibrate if you flew too high, some always flew to the left, and some just didn't fly.
Am I correct or both are correct?
You are saying this sentence will be grammatically correct too without last "and"?
– rzd85 Jul 14 '17 at 17:08