Which sentence states a fact?
A: The First World War was waged for no good reason.
B: The First World War began in 1914 and ended in 1918.
The first sentence states a fact.
The First World War began in 1914 and ended in 1918.
It can be proved by reading a book about the First World War.
The second sentence states an opinion.
The First World War was waged for no good reason.
Good shows what a person believes, thinks, or feels. Another person might have a different opinion about whether or not reasons are good.