was不是is和am的过去式吗?were不是are的过去式吗?为什么可以用if i were a boy?而不用if i

was不是is和am的过去式吗?were不是are的过去式吗?为什么可以用if i were a boy?而不用if i was a boy?

if I were 是固定语法,指虚拟情况.I was 指实际的,如 I was very angry then.