1

1) had had

2) had done

3) had stopped

4) had missed

5) had written

2

1) had done; phoned

2) repaired; had come

3) had visited

4) entered; understood; had been

5) had written; went

3

1) I had done my homework.

2) I repaired my computer.

3) I had trained.

4) I had found it.

5) I had woken up.