This document discusses the use of the word "wish" and "if only" to express regrets or wishes for unlikely or impossible things. It explains that "wish" can refer to past, present, or future unreal conditions, while "if only" means the same as "I wish" but is stronger. Examples are provided to illustrate using wish with the past simple and past perfect tenses to refer to present or past regrets/wishes. The document also gives structures for using "wish" to complain about annoying habits or things one would like others to do or not do.