Question

investigar el uso de was y were

Answer 1

El verbo was es el pasado del verbo be ser o estar 

Was lo utilizas con las personas del singular i, he, she, it. 
were lo utilizas con las personas del plural you, we, they y you del singular. 

I was born in Mexico= Yo naci en Mexico. 
We were study on German= Nosotros estudiamos en Alemania.

Answer 2

el "was" y "were" son el pasado del verbo to be
el was se utiliza para:
I, she, he, it
mientras que were usamos con:
you, we, they

significan: estaba o estabamos, era o eramos
ejemplos:
I was born in 2000
you were an excelent studient at the school

en forma netaviva utilizas was not y were not. Su contraccion es: wasn't y weren't respectivamente.
su estructura es la siguiente:
S + was/were + C (afirmativa)
S + was/were + not + C (negativa)
was/were + S + C ? (interrogativa)