Which sentence states a fact?
A: In the Middle Ages, knights rode horses and wore armor made of metal.
B: Knights during the Middle Ages were really just bullies on horseback.
The first sentence states a fact.
In the Middle Ages, knights rode horses and wore armor made of metal.
It can be proved by reading a book about knights.
The second sentence states an opinion.
Knights during the Middle Ages were really just bullies on horseback.
Bully shows what a person believes, thinks, or feels. Another person might have a different opinion about whether knights were bullies.