Introduction: The Meanig of a Verb
The verb is the most important word in a sentence. Metaphorically speaking the role of a verb can be likened to a search engine on the internet; without such simple software program all those billions of electronic pages on the world-wide-web would not be accessible for criteria matching.
In terms of verbs Latin is King. Learning all the Latin conjugations, moods, tenses and voices can be daunting. To ease the task of learning Latin verbs it is important to understand what verbs try to do. For this reason I feel the following preamble may be useful.
A verb can express definitive past, present and future actions. Verbs are also endowed with a kind of sensitivity level as they can distinguish between actions that took place in the remote past -perfect past- or in the recent past- the imperfect. Similarly a verb in the Present tense can express an action that is happening now and is completed or is continuing. Verbs used to express the Future tense actions can be of two types, those that express a simple action that will happen in the future, and those that are capable of catapulting the subject into the fartherest future and yet look back at it as a past action. The power of the mind is formidable. We have the mental capability of projecting ourselves in mental scenarios at a speed greater than the speed of light. But we do not yet understand how it works. When we do we will become incolae of other galaxies.
The illustration below tries to convey graphically what we have just said about verbs.

In Latin verbs can be of two kinds: predicative and copulative.
Predicative verbs are those that express a meaning of completeness: Mary studied; England won the cup. In these two examples the meaning of the subject is complete and does not need further explanation. Because of this sense of completeness the verb is said to be a verbal predicate1.
Copulative verbs, on the other hand, are those that once expressed do not convey a sense of completeness, they beg the question so to speak; thus they require another word to make clear its meaning and endow the subject with completeness. Examples:
I am. (so what, yuo are who, you could say)
I became. (you became what)
I stay. ( you stay where, when)
Because of this sense of incompleteness each of the verb am, became, stay is said to be of the type nominal predicate.
Stay the course. If you are learning Latin you have to know your grammar; and once you do, you are in control of yourself, and probably others.
Form or Voice of Latin Verbs
Latin verbs can also have a specific form or voice, viz. they can be active or passive.
A verb is active when the subject of the sentence is the word that is doing the action expressed by the verb; in other words it carries out the action expressed by the verb. Mary loves John. Mary reads the book.
A verb is passive when the subject of the sentence suffers the action expressed by the verb: Mary is loved by John, Mary is read the book.
Active verbs can be transitive or intransitive.
A verb is transitive when the action of the verb passes fron the subject to the direct object. In the example Mary reads the book, the verb reads is transitive because the action from the subject (Mary) passes unto the direct object (the book).
A verb is intransitive when the action of the verb remains on the subject or passes to an indirect object. In the example The money has vanished, the verb has vanished is intransitive because it does not require anything else to convey its meaning of completeness. In one example, The soldiers marched, the action remains on the subject therefore the verb marched is intransitive. In this other example The soldiers obey their generals, the action from the subject (the soldiers) passes unto an indirect object (their generals), therefore this verb in Latin would be intransitive. In English, however, it is classified both as a transitive and intransitive verb.
Rule of thumb: in Latin those verbs that support the accusative (i.e. the direct object) are transitive verbs. Second rule: only transitive verbs can be changed from active to passive.
Third rule: to turn an active sentence in a passive sentence just make the object of the active sentence into the subject of the passive sentence, in other words invert the role of the subject and object of the sentence, and use the auxiliary verb to be.
Here are some examples:
Active: The soldiers defend their country.
Passive: The country is defended by the soldiers.
Active: The Hadrian wall defended England.
Passive: England was defended by the Hadrian wall.
Mood of a verb
The mood of a verb shows the attitude of the speaker in his utterance. It can express:
Certainty - using the Indicative Mood
Possibility - using the Subjunctive mood
Desire - with the Conditional mood (this mood does not exist in Latin; remember Caesar's "Veni, Vidi, Vinci")
Command - using the Imperative mood.
Tense of a verb
The tense of a verb refers to the chronological relationship between the time when one speaks and the time when the action expressed by the stated spoken verb refers to; in other words, past, present and future and those in between.
Person of a verb
The person of the verb specifies which individual amongst those involved, directly or indirectly, in the sentence, is referred to by the verb. In other words, I, you, he-she-it, we, you, they.
Number of a verb
Numbers are allways teo, singular and plural.
Refer to the section on the right hand side for a full list of verb moods and tenses.