The document discusses the uses of "be going to" and "will" to express future events or plans. "Be going to" is used to talk about situations in the present that make a future event likely or certain. "Will" can be used to talk about decisions made at the time of speaking or to make predictions based on present evidence. The document provides examples of using these structures to talk about plans for the day, predictions about the weather, having a baby, and decisions about drinks and phone calls.