The document provides examples of using "if only" and "wish" to express wishes and regrets in English. It explains that "if only" or "wish" can be used with the past perfect or past simple tense to talk about something that didn't happen in the past but is wished to have happened differently. It also gives examples of using "wish" or "if only" with "would" to express a desire for a present or future situation to be different than it is. The document includes examples sentences to demonstrate how to use "if only" and "wish" correctly in different tenses and situations.