Question

Como se usa el was y el were cuando hay el your?

Answer 1

Primeramente hay que aclarar que was y were son equivalentes en cuanto a tiempo, en cuanto a personas, es distinto.

"Your" es un determinante posesivo, por lo que solo se puede usar "was o were" en objetos de pertenencia de la segunda persona... Aquí unos ejemplos:

-Afirmativas:
Your dog was lost yeaterday.
Your tenis were very clean.
Your teacher was the best.

-Negativas:
Your toys weren't here.
Your dad wasn't there.
Your cat wans't dead, it was just lost.

Preguntas de si y no:
Was your sister here?
Were your grandparents married?
It was your dog?

Si te fijas en las preguntas, cambia el formato de la frase, de modo que:

Where o Was+determinante+pertenencia+verbo o complemento

Were para plural
Was, singular

Espero haberte ayudado.