Отрицательное: David was not watching a football match at 9 in the evening yesterday.

Вопросительное: Was David watching a football match at 9 in the evening yesterday?

Отрицательное: My friends were not preparing for the picnic the whole evening.

Вопросительное: Were my friends preparing for the picnic the whole evening?

Отрицательное: Alec did not collect music discs when he was a schoolboy.

Вопросительное: Did Alec collect music discs when he was a schoolboy?

Отрицательное: He did not come to the office at 9 o’clock last year.

Вопросительное: Did he come to the office at 9 o’clock last year?

Отрицательное: The sportsmen were not preparing for the competition when the rain started.

Вопросительное: Were the sportsmen preparing for the competition when the rain started?

Ответ:

1.David wasn't watching a football match at 9 in the evening yesterday.

1.Was David watching a football match at 9 in the evening yesterday.

2.My friends weren't preparing for the picnic the whole evening.

2.Were me friends preparing for the picnic the whole evening.

3.Alec didn't collect music discs when he was a schoolboy.

3.Did Alec collect music discs when he was a schoolboy.

4.He didn't come to the office at 9 o'clock last year.

4.Did he come to the office at 9 o'clock last year.

5.The sportsmen weren't preparing for the competition when the rain started.

5.Were the sportsmen preparing for the competition when the rain started.