The teacher said that uncertain statements are not propositions, so

Let's start with a question of principle. Proposition is a sentence to judge whether an event is true or not. Second, a proposition is true, the correct proposition is called true proposition, and the wrong proposition is called false proposition. Third, the sentence you gave is a judgment sentence, so it is a proposition, but it is hard to say whether it is true or not.

The brothers upstairs didn't point out the real crux of the problem.