The document discusses the subjunctive mood in English grammar. It notes that there are two forms of the subjunctive mood: the BE-subjunctive, realized by the base form of the verb, and the WERE-subjunctive, realized by using "were." It then outlines several common uses of the subjunctive mood, including to express a command, desire, hypothesis, purpose, doubt or supposition. It provides examples of how the subjunctive is used with "if" clauses to express hypothetical situations.