Here are some examples:
* un- (meaning "not") added to "happy" makes unhappy
* pre- (meaning "before") added to "game" makes pregame
* super- (meaning "above, beyond") added to "market" makes supermarket
Prefixes can:
* Change the meaning of the word completely (like "happy" to "unhappy")
* Create a new word with a different meaning (like "game" to "pregame")
* Make the word more specific (like "market" to "supermarket")
Prefixes are very common in English and other languages, and they can be really helpful for understanding words and their meanings.