The subject is the book and papers that are stacked
Parallelism in rhetoric is used to persuade, motivate, and/or evoke emotional responses in an audience and is often used in speeches. The balance between clauses or phrases makes complex thoughts easier to process while holding the reader or listener's attention.
They shouldn’t rush students and if one person doesn’t know how to do something don’t get mad and help them. Don’t get mad if he /she takes a holiday off instead kindly ask them the reason