`1`. Before Fred had spent his holiday in Italy he wanted to learn Italian.
`2`. Jill had phoned Dad at work before she left for her trip.
`3`. Susan turned on the radio after she had washed the dishes.
`4`. When she arrived the match had already started.
`5`. After the man had come home he fed the cat.
`6`. Before he sang a song he had played the guitar.
`7`. She watched a video after the children had gone to bed.
`8`. After Eric had made breakfast he phoned his friend.
`9`. I was very tired because I had studied too much.
`10`.They had ridden their bikes before they met their friends.
`→` Past perfect:
`(+)` S + had + VpII + ......
`(-)` S + hadn’t + VpII + .....
`(?)` Had + S + VpII ?
`→` Past simple:
`-` Với động từ tobe
`(+)` S + was/ were +…
`(-)` S + was/ were + not + ....
`(?)` Was/ Were + S +…?
`-` Với động từ thường:
`(+)` S + V-ed +…
`(-)` S + did not + V(nguyên mẫu)
`(?)` Did + S + V(nguyên thể)?