*Cấu trúc quá khứ hoàn thành:
`->` S + had/hadn't + Pii + ......
`1` . We had just heard the news when you rang.
`2` . I had already though of that before you suggested it.
`3` . When I turned on the TV, the programme had already started.
`4` . She was hungry because hadn't eaten anything all day.
`5` . By the time I left school , I had decided to become a musician.
