When you rate products on Amazon, do you just get one vote for "this is my favorite product" and you can't express any opinion about any of the others? When s

When you rate products on Amazon, do you just get one vote for "this is my favorite product" and you can't express any opinion about any of the others? When students are evaluated by their teachers, do the teachers just say "this student is the best" and not express anything about any of the others?