Work hard - teacher, learn poems by heart- pupils, have holidays many times a year - pupils, give instructions - teacher, wear jeans - teacher, play jokes - pupils, be very polite - я лично считаю что и те и те (either), но наверное про учителя больше(teacher), talk loudly during the break - pupils, do homework every day - pupils, copy long sentences- pupils, give bad marks - teacher, get goos marks - pupils.