The document discusses the definite and indefinite articles in English - "the" and "a/an".
It provides examples of when to use the definite article "the", such as when referring to something already mentioned or known to both the speaker and listener. It also lists contexts that take the definite article, such as with superlatives and ordinal numbers.
The document also explains the uses of the indefinite article "a/an", such as when referring to something for the first time or referring to a single object or person. It notes the rules for using "a" versus "an" depending on whether the following word starts with a vowel or consonant sound.