Changs from singular to plural
l am student
he is a teacher
this is my book
the girl is in the room

I am student . - We are students.

He is a teacher . - They are teachers.

This is my book . - These are my books.

The girl is in the room. - The girls are in the room.

I am a student-we are students

he is a teacher-they are teachers

this is my book-these are our books

the girl is in the room-the girls are in the rooms