Найдите и исправьте ошибку в каждом предложении. Find and correct the mistake in each sentence.

1. There are a book on the table.

2. There is two girls in the classroom.

3. Is a boy there in the café?

4. Are two chairs there at the table?

5. There not is a flower in the vase.

6. There not are three books in the bag.

7. There are a cat in the room.