Объяснение:

1. Mother had cooked supper by 7 o'clock.

2. Meg said that she had been in this city.

3. The pupils were discussing this problem the whole evening.

4. When I came into her room, she was playing the piano.

Питання:

1. Had mother cooked supper by 7 o'clock?

2. Did Meg say that she had been in this city?

3. Were the pupils discussing this problem the whole evening?

Заперечення:

1. Mother had not cooked supper by 7 o'clock.

2. Meg did not say that she had been in this city.

3. The pupils were not discussing this problem the whole evening.