The document provides guidance on expressing opinions in American English. It explains that an opinion is how an individual feels about something and should not be stated as a fact. It offers phrases to introduce personal opinions like "In my opinion" or "Personally, I think." The document also suggests starting a general opinion with phrases like "It is thought that" and providing reasons and details to support opinions. Finally, it notes that in responding to opinions, one can agree or disagree and provides examples of language for both.