Let's look at some examples of the verbe "to be" in Present Simple:
This is my sister. She is eleven years old.
I am an engineer. This is my car.
My parents aren't here. They are at home.
Singular
I am
You are
He/she/it is
Plural
You are
We are
They are
Singular
I 'm
You 're
He/she/it 's
Plural
You 're
We 're
They 're
Singular
I am not
You are not
He/she/it is not
Plural
You are not
We are not
They are not
Singular
I 'm not
You 're not
He/she/it 's not
Plural
You 're not
We 're not
They 're not
She's my cousin. He's my teacher.
I'm from Canada. They're Korean.
I'm Jane and this is my friend Jack. We're from USA.
I'm Peter and these are my cousins.
It's hot outside.
It's a beautiful day.
Paris is the capital of France.
Canada is in the north of America.
I'm 32 years old.
My grandpa is very old.