This document discusses the use of "so" and "neither" when agreeing or disagreeing with statements made by others. It explains that "so" is used when statements are affirmative, such as "John is a student, so am I." "Neither" is used when statements are negative, like "John isn't a doctor, neither am I." Examples are provided to illustrate the proper use of these words depending on whether the original statement and the agreeing statement are positive or negative.