How much do you really know about Ancient Rome? - Stephanie Honchell Smith

A century is a period of 100 years. It is a common unit of time used to group historical events and long durations.

A large number or amount of people or things. It can also refer to a specific group of people or things, or a piece of land used for a particular purpose, like a parking lot.

An empire is a group of states or countries ruled over by a single monarch, an oligarchy, or a sovereign state. It can also refer to a large commercial organization that is owned or controlled by one person or family.

"It's" is a contraction of the words "it is" or "it has". It is used to identify objects, describe conditions (like weather or time), or express that something has happened.