Question

agente usa was ou were no


when.......


why......


complete


depois explique o por que do uso deles

Answer 1

was é usado com I, he, she e it quando o verbo to be está no passado

were é usado com you, we e they

isso acontece porque o verbo to be é um verbo irregular, então, ao invés de acrescentarmos ed, usamos a sua forma irregular que são were e was

Answer 2

É possível usar ambos nas duas sequencias :

When I was a child, I had a video-game

e podemos usar para:

Why I was there with you?

Was é  apenas para o singular e Were apenas para o plural, então Were será usado na terceira pessoa (lembrando q was e were é passado):

When their were here, their got a lot of candies

Why were their here?

Ele é usado na terceira pessoa pois esta com o WHEN e o WHY, mas pode ser usado com WE, daí fica:

We were he.

Espero ter ajudado.