Question

o was so e usado quando l he she e it no final da palavra

Answer 1

I WAS
YOU WERE
HE WAS
SHE WAS
IT WAS
WE WERE
YOU WERE
THEY WERE

Answer 2

Você pode usar o was em qualquer lugar do texto. Creio que sua pergunta é se com os pronomes I/he/she/it é que se usa o verbo to be no passado simples. Se for esse o caso, a resposta é sim. 
Mas o was pode ser usado na pergunta e na resposta, na forma afirmativa e na interrrogativa. Para negar, some was com not que, contraídos, se tornam wasn´t.