If i had been invited to your birthday party,i would have bought a birthday gift for you.若我想把这句话写成独立主格结构 那么if引导的从句该如何改写?

问题描述:

If i had been invited to your birthday party,i would have bought a birthday gift for you.若我想把这句话写成独立主格结构 那么if引导的从句该如何改写?我是这么写的:Having been invited to your birthday party,i would have bought a birthday gift for you.可别人说这么不对.希望有人能帮忙改下这句话.

原句是虚拟 并未发生 而你改完的句子则表示被邀请是既定的事实 这句话可以改成同义句:Had been invited to your …… 似乎改不了独立主格