Preschools are often varied in the amount of time that the child will spend at the actual school. In most cases, the preschool aged child does not have the attention span to remain at school longer than a few hours. If your school only has class for two hours, realize that is due to their ability to hold the child's attention.
When considering various preschools in your local area, take the time to consider their curriculum. When interviewing the school, ask what their curriculum is. This will give you a clear indication of what will be taught at the school. It will provide the parent with the necessary information to make the right decision about one school or the next.