For example:
The child is playing in the park.
The children are playing in the park
My favorite .._______(book/books) is on the shelf.
My favortie book is on the shelf.
The .._______(dog/dogs) in the yard are barking loudly.
The dogs in the yard are barking loudly.
She bought three .._______(apple/apples) at the grocery store.
The .._______(car/cars) in the parking lot are all red.
Each .._______(person/people) has a unique perspective.