The document discusses the use of "used to" and "would" to express habitual actions in the past. "Used to" is followed by an infinitive and refers to past permanent situations or repeated actions, like "I used to have long hair." "Would" takes an infinitive without "to" and also refers to repeated past actions, like "She would leave early." The phrase "get/be used to" means to become accustomed to something and is always followed by an "-ing" verb, like "I'm not used to living in the city." Several examples of correct and incorrect usage of these forms are provided.