They are excited.
They were excited.
I am late for school.
I was late for school.
I'm not hungry. I'm thirsty.
I wasn't hungry. I was thirsty.
They are firefighters. They aren't policemen.
They were firefighters. They weren't policemen.
The party is fun.
The party was fun.
We are hot.
We were hot.
You are bored.
You were bored.
You are a student.
You were a student.
She isn't a doctor. She's a nurse.
She wasn't a doctor. She was a nurse.
History class isn't fun. It is boring.
History class wasn't fun. It was boring.
She is happy.
She was happy.
He isn't busy.
He wasn't busy.