The document discusses the verb "to be" and how to use it in the present, past, and future tenses. It defines "to be" as a verb that shows existence and can be used to describe present, past, or future time. Examples are provided of using the verb in the present tense, such as "I am a student", past tense, like "I was a student in 1990", and future tense, such as "I will be a student next year".