Теория:

Study some information about the verb 'to be' in the Past Simple.
Для того, чтобы сказать о том, где вы были вчера или несколько минут назад, вам необходимо использовать глагол to be в прошедшем времени.
Посмотрим, как строятся утвердительные предложения с глаголом to be.
 
I was

you were

he, she, it was

We were

You were

They were
 
 
Examples:

I was at school yesterday.

My friend was in the shop last Sunday.
  
shop-interior.jpg
Чтобы сообщить о том, что вы не были где-то или определенный предмет не обладал такими качествами, вам необходимо использовать глагол to be + частицу not.
was not

you were not

he, she, it was not

We were not

You were not

They were not
  
  
Examples:
  
They were not at the party.
  
Mary wasn't happy.
  
shutterstock_2670552471-390x285.jpg
 
Запомните сокращенные формы отрицаний:
 
was not = wasn’t

were not = weren’t
Источники:
http://www.papawestray.co.uk/papay-shop.html
http://www.thejournal.ie/unhappy-people-dont-die-younger-2491663-Dec2015/