The document discusses the uses of gerunds and infinitives in English. Gerunds can function as subjects, objects of prepositions, or complements of verbs. Infinitives can also function as subjects or complements of verbs. Some verbs are followed by gerunds or infinitives with no change in meaning, while others require a gerund or infinitive to change the meaning. Certain structures like "too ADJ to VERB" also use infinitives.