The English Active Voice
The English Active Voice is used to indicate the relationship between a verb and its subject. Active Voice is employed when the verb indicates what the subject of a sentence is or does. For example:
John walks down the street.
Mary is a good student.
Notice that in both cases, the verb in each sentence (walks and is) indicates what the subject (John and Mary) is or is doing. Of course, the active voice can be used in all verb tenses to indicate what the subject is, was, or will be or what the subject is doing, was doing, or will do.
Keep in mind that the voice of a verb can be employed using any of the other characteristics of a verb. For example, the active voice can be used with any person (first, second, third), number (singular or plural), tense (present, past, future, present perfect, past perfect, future perfect), or mood (indicative, subjunctive, imperative) for which a form exists. However, not all forms exist. For example, there is typically no future perfect imperative mood. There is a theoretical one, it is just not considered to be a part of proper English grammar. This fact becomes increasingly apparent to students of Latin who must use distinctive inflections to form the five verb characteristics.