The document discusses opinion-marking signals, which are words or phrases that indicate feelings, emotions, and attitudes towards something. Some common opinion-marking signals include "personally", "in my opinion", and "in my experience". The document provides examples of introductory words and phrases used to express opinions, such as "I think", "I believe", and "from my point of view". It also lists words that are often used to express opinions like "always", "never", "better", and "best". Finally, the document gives examples of using opinion-marking signals to express views about products, general matters, and preferences.