Which sentence states a fact?
During the Civil War, Frederick Douglass spoke to President Abraham Lincoln about the treatment of African American soldiers. Of all those who fought to put an end to slavery in America, the writer and abolitionist Frederick Douglass had the greatest influence.
A fact is something that can be proved by research or observation.
Napoleon Bonaparte was shorter than King Louis XVI.
The statement above is a fact. The statement can be proved by researching the height of each man and comparing them.
An opinion is something that a person believes, thinks, or feels. An opinion cannot be proved.
Napoleon Bonaparte was a better leader than King Louis XVI.
The statement above is an opinion. People can have different ideas about what makes someone a "better" leader, so the statement cannot be proved.
The second sentence states a fact.
During the Civil War, Frederick Douglass spoke to President Abraham Lincoln about the treatment of African American soldiers.
It can be proved by reading Frederick Douglass's autobiography.
The first sentence states an opinion.
Of all those who fought to put an end to slavery in America, the writer and abolitionist Frederick Douglass had the greatest influence.
Most influential shows what a person believes, thinks, or feels. Another person might have a different opinion about which abolitionist had the greatest influence.