There is an extensive scientific literature and body of practice on both the theory and technique of CV.
There is extensive reading and practice on the topic of CV.
Little to nothing is known about CV.
A black man is sitting in a chair
The Era of Good Feelings can be used to describe the years after the War of 1812.
The girl watches her reflection.
A child is in a store.
There are no reasons why there are differences.
People are posing for a picture.