NOD OFF Definition: (informal) to go to sleep, usually unintentionally, while sitting down. E.g.1: After dinner he nodded off in the armchair. E.g.2: The lesson was so boring that one of the students nodded off. This phrasal verb cannot be separated.

NOTE (something) DOWN Definition: to write important information on paper so that you can remember it or refer to it later. E.g.1: She noted the answers down so that she could try the exercise again later in the week. E.g.2: The teacher noted down their mistakes to help him prepare for the next lesson. This phrasal verb can be separated. (E.g. 1)