had been to 是什么時態

　　Oh, I had been to the airport that time.

　　哦，那時我已經去機場了。

　　My friend learned that the police had been to the flats.

　　我的朋友得知警察來過大樓。

　　I had been to Penn only one day, in October of my senior year.

　　我只在賓夕法尼亞州立大學呆過一天，那是在我畢業那年的十月份。