The document discusses causative structures in English. There are two basic causative structures - active and passive. In the active structure, one person causes another to do something, such as "I had John fix the car." In the passive structure, something is caused to be done but the agent is not specified, such as "I had the car fixed." Common causative verbs are have, get, make, and let. Have and get can be used in both active and passive structures, while make implies forcing someone and let implies allowing.