Подскажите пожалуйста: как сокращать глагол to be: am, is,are.

I am → I'm  he is → he's  she is → she's  it is → it's  you are → you're  we are → we're  they are → they're

’m = am,  ’re = are, ’s = is;  aren’t = are not,  isn’t = is not