Ответ:

1.Was my son ill last week?

My son wasn't ill last week

2.Are they free on Sunday?

They aren't free on Sunday

3. Is it cold today?

It isn't cold today

4.Will be our engineer busy tomorrow?

Our engineer won't be busy tomorrow

5.Are the classes over at 4 o'clock?

The classes aren't over at 4 o'clock

6.Is your friend fond of music?

Your friend isn't fond of music

7. Were they absent yesterday?

They weren't absent yesterday

8.Was she in the cinema on Tuesday?

She wasn't in the cinema on Tuesday

9. Will the children do this work themselves?

The children won't do this work themselves

10.Were both girls in the garden?

Both girls weren't in the garden

11.Am I your daughter?

I am not your daughter

12.Will be lectures on Physics on Monday?

Lectures on Physics won't be on Monday

13.Are there many mistakes in his test?

There aren't many mistakes in his test