Which sentence states a fact?
Mummifying a pet cat is a strange thing to do. Some ancient Egyptians mummified, or preserved, their pets' bodies.
A fact is something that can be proved true by research or observation.
George Washington became president of the United States in 1789.
This statement is a fact. It can be proved by researching what year George Washington was inaugurated president.
An opinion is something that a person believes, thinks, or feels. An opinion can be supported by evidence, but it cannot be proved true.
George Washington was a better president than Thomas Jefferson.
This statement is an opinion. People can have different ideas about what makes someone a "better" president, so the statement cannot be proved.
The second sentence states a fact.
Some ancient Egyptians mummified, or preserved, their pets' bodies.
It can be proved by researching ancient Eyptian culture.
The first sentence states an opinion.
Mummifying a pet cat is a strange thing to do.
Strange shows what a person believes, thinks, or feels. Another person might have a different opinion about what actions are strange.