Student or Learner
Are the following correct?
You should read your book.
He should stay in his room.
They shouldn't waste their time.
I should use my mobile.
She should sit in her chair.
We should write in our notebook
I have changed your thread title. None of your sentences contains an objective pronoun, which are 'me', 'you', 'him', 'her' and 'them'.
They are correct except for the last one, which should end '...notebooks' followed by a full stop (period).
Click here to read about possessive adjectives.