The document discusses how to rewrite sentences using passive voice constructions with "it is said that", "is said to", "(be) supposed to", and "not supposed to". It provides examples of active sentences and their passive rewrites. Key passive constructions are "it is said that" to report what people say, "is said to" and "(be) supposed to" to indicate what is planned or expected, and "not supposed to" for what is not allowed. The document also notes that these passive forms can have overlapping meanings in some cases.