The document discusses various hypothetical constructions in English including wishing for past, present, or future situations using "wish", expressing preferences using "I'd rather" or "I'd prefer", describing unlikely present or past scenarios using "if only", indicating that it is time to do something using "it's time" or "it's high time", and describing seemingly true but untrue present or past situations using "as if" or "as though". These constructions are used with different verb tenses to indicate whether the hypothetical situation is present, past or future.