I would
I would+動(dòng)詞原形
I'd see
I'd walk
I'd study
If I were you, I'd rather go.
如果我是你,我就去
If I were rich,I'd travel around the world.
如果我有錢,我就去環(huán)游世界
I had
I had+過去分詞構(gòu)成過去完成時(shí)
I'd seen
I'd walked
I'd studied
He'd already left when we arrived.
當(dāng)我們到的時(shí)候,他已經(jīng)走了
I felt absolutely certain that I'd seen her before.
我完全確信自己以前曾見過她