This document provides information about time clauses and expressions of regret and hypothetical situations in English. It defines various time clauses like "by the time", "until", and "as soon as" and provides examples of their usage. It also contrasts the uses of "since" and "until". Additionally, it discusses expressing regret using "should/shouldn't have" and describing hypothetical situations with "if". The document includes practice activities matching time clauses and fill-in-the-blank exercises to reinforce the topics.