We use the verb "be" in Present Simple when we want to
say who somebody is - He is Rob.
say what something is - That is my mobile phone.
say where somebody is from - We are from Ireland.
say how we feel - You are hungry.
say where somebody or something is - She is at school. My book is on the table.
describe somebody or something - They are clever. Your jacket is nice.
talk about people's jobs - My mother is a teacher.
talk about somebody's age - I am fifteen years old.
talk about somebody's health - Ann is ill.
talk about the weather - It is cold today.
say that there is something somewhere - There is a book on the table.
Full formShort form
I amI'm
we arewe're
you areyou're
they arethey're
he ishe's
she isshe's
it isit's
Full formShort form
I am notI'm not
we are notwe aren't
you are notyou aren't
they are notthey aren't
he is nothe isn't
she is notshe isn't
it is notit isn't
Am I …?Yes, I am.No, I'm not.
Are we …?Yes, we are.No, we aren't.
Are you …?Yes, you are.No, you aren't.
Are they …?Yes, they are.No, they aren't.
Is he …?Yes, he is.No, he isn't.
Is she …?Yes, she is.No, she isn't.
Is it …?Yes, it is.No, it isn't.
Note: In short answers we use pronouns (I, we, you, they, he, she, it)
— Is Maria a teacher?
— No, she isn't.
(Not: No, Mary isn't.)