substitute the underlined nouns by subject pronouns
a- Paul is a studant
b- the book has 136 pages
c- Richard and i want to play

2- substitute the underlid by object pronouns

a- I don't understand john
b- you brought Lisa and me a present
c- where did you buy those books

3- use subjet and object pronouns

a- diana and bill inveted my sister to their wedding

b- margareth knows boys very well

c- carlos is reading the book to my little brother