1.

There was a sofa in the bedroom.

2.

There were two sofas in the bedroom.

3.

Was there a sofa in the bedroom?

4.

Were there two sofas in the bedroom?

5.

There wasn't (o There was not) a sofa in the bedroom.

6.

There weren't (o There were not) two sofas in the bedroom.

7.

There were some sofas in the bedroom.

8.

There was no sofa in the bedroom.