Ответ:

1. Do children swim in the river?

Yes, they do. / No, they don't.

Children don't swim in the river.

2. Did you help mother about the house?

Yes, we did. / No, we didn't.

We didn't help mother about the house.

3. Did Pete break the window?

Yes, he did. / No, he didn't.

Pete didn't break the window.

4. Are birds singing songs in spring?

Yes, they are. / No, they aren't.

Birds aren't singing songs in spring.

5. Does Kate clean the room?

Yes, she does. / No, she doesn't.

Kate doesn't clean the room.