Ответ:

Ex 2.

1.didn't know; had not told.

2.know; had arrived.

3.had been snowing; was.

4.had covered; came.

Ex 3.

1.had fallen.

2.had been conducting; had gone.

3.had.

4.had been working; had been.

5.had commited; had disguised.

Объяснение: