`2)` The postman had left by the time Fred opened the door.

`->` by the time: tới khi

`->` S + had + V3 + by the time + S + V-qk ... 

`3)` I had never won a competition before.

`->` S + had + never + V3 ... before: chưa từng làm sao trước khi HĐ xảy ra trong QK

`4)` Dennis answered his mobile phone after he had stopped the car.

`->` S + V-qk ... 

`->` clause `(1)` + after + clause `(2)`: sau khi

`5)` When Brian arrived with the pizza, the film had already started.

`->` S + had + already + V3 + when + S + V-qk ... : ai đã làm gì trước khi ai làm gì trong QK

`6)` We arrived at the party before it started to rain.

`->` clause `(1)` + before + clause `(2)`: trước khi

`7)` She had dinner after she had a shower.
`->` S + V-qk ...

`->` clause `(1)` + after + clause `(2)`: sau khi

`-`

@magnetic