Respuesta:
I was happy.
You was sad.
He was hungry.
She was beautiful.
It was cold and windy yesterday.
We were at the park last sunday.
They were studying.
We were at school last year at this time.
Explicación:
Was: Cuando habla de una sola persona, en singular (im, is, you, he, she)
Were: Cuando habla en plural o se refiere a varias personas. (they, we, us)