We aren’t at school today.
We weren’t at school yesterday.
I am not at my desk.
I wasn't at my desk.
You aren’t rich.
You weren’t rich.
I'm happy today.
I was happy yesterday.
I am tired today.
I was tired yesterday.
They are in Paris today.
They were in Paris yesterday.
It's hot and sunny today.
It was hot and sunny yesterday.
It’s my birthday today.
It was my birthday yesterday.
She isn’t in the sports hall.
She wasn’t in the sports hall.