(+) Bob is crying in the yard.
(-) Bob isn't crying in the yard.
(?) Is Bob crying in the yard?
Who is crying in the yard?
What is Bob doing?
Where is Bob crying?
Bob is crying in the yard, isn't he?
(+) The girls are watering flowers in the garden.
(-) The girls aren't watering flowers in the garden.
(?) Are the girls watering flowers in the garden?
Who is watering flowers in the garden?
What are the girls doing?
Where are the girls watering flowers?
What are the girls watering?
The girls are watering flowers in the garden, aren't they?