Ответ во вложении ниже.
Для справки:
Past Perfect образуется так: had + третья форма глагола (done, had, studied, worked и т.п.)
HAD - вспомогательный глагол, к нему присоединяется отрицательная частица not:
I hadn't read the book before I watched the film.
1. He has just come home
2. visits
3. are watching
4. have been reading
<span>1. Nobody (knew) where Smith (had gone). 2. A girl who (was standing) under the beech
tree (came) up to us. 3. Mary (was speak</span><span>ing) to Mr Boxwell when I (saw) her in
the corridor this morning. 4. John (was park</span><span>ing) the car in Fifth Avenue when a
young man in black glasses (appeared) from nowhere and (stood) before
him. 5. He again (came) to the village where he (had lived) in childhood. 6.
While we (was talk</span><span>ing), there (came) a loud knock at the door. 7. He (looked)
into the drawing-room. The old man (was sleep</span><span>ing) peacefully in the armchair at
the fire-place. 8. When their visitor (left) John and his mother
(were stand</span><span>ing) near the window. 9. When he (had dressed), he (went) downstairs, (wrote)
a long letter to his parents and another to his sister. 10. She
(welcomed) her with a bright smile and (turned) back to the offensive dandy
lions she (had been fight</span><span>ing) with. 11. While she (was read</span><span>ing) this notice, a middle-aged
woman (appeared) in the doorway. 12. When he (came) back to the
conference room, he (saw) that the situation (had changed). 13. She (had been sitt</span><span>ing) at
the table only five minutes when a car (came). 14. Their father (was)
still silent, even when they (had had) coffee. 15. The three (sat) down to
the meal that Susan (had prepared). 16. He (was sitt</span><span><span>ing</span>) thinking of his wife whom he
(had lefr) alone in Europe. 17. They (looked) over the accounts together and
(found) where she (had made) her mistake. 18. I (was) surprised at John's
failure because he (had been) such a good student previously.
</span>
2) he is, is it?, it is
3) they are, it is
