Voice

Voice demonstrates clearly the link between subject and verb in a sentence by stating who carried out the
action. There are only two voices -- active and passive -- and every verb expresses one or the other. Look at
this sentence:

(1) John loves Mary.

Here, John is the subject of the active verb, while Mary is the direct object of the action. Now, if we transform
this into the passive voice, we get

(2) Mary is loved by John.

Grammatically, Mary is now the subject of the passive verb even though she is still "being loved" and is the
"passive recipient" of John's affection. In (1), it is important to know that John loves Mary, that he is the one
who loves, and that Mary's view on John does not play a role here. Where Mary is the subject, we are
stressing the same fact, i.e., that she is loved, and although we still don't know how she feels, she is the focus of
our attention as subject.

In many passive sentences we never find out who actually carries out the action because we want to highlight
the subject who received it. The choice between active and passive depends on what you want to emphasize in
the sentence. In (2), John is the agent (or the actor, from the Latin agere, to act). In fact, "by John" could be
omitted altogether because the sentence structure stresses the fact that Mary is loved, giving the agent a less
important role:

(3) Mary is loved.

Notice how the passive verb form is derived. It uses the auxiliary "to be" again, plus the past participle of the
verb. The tense is carried by the auxiliary, not by the participle. The participle remains unchanged in passive
contructions. For example, in the following, the participial form remains the same regardless of the tense of the
verb:

Passive verb forms

I am being                 driven         to Montreal in three hours.
Pres. prog.
TO BE         +         PAST PARTICIPLE         
I have been                driven         to Montreal twice this year.
Pres. perf.
TO BE         +          PAST PARTICIPLE         

Compare these forms with present progressive forms in an active voice:

Active verb forms

I am                   driving         to Montreal tomorrow.
Simple Pres.
TO BE         +         PRESENT PARTICIPLE         
I have                 driven         to Montreal twice this year.
Simple Pres.
TO HAVE         +    PAST PARTICIPLE         

Mood

The third aspect of the verb is mood -- and every verb is in one of the three moods:

  •   Indicative
  •   Imperative
  •   Subjunctive

Indicative

The most common verbal mood is the indicative, since the most common purpose of a verb is to state a fact, to
"indicate" something that is real. In the following sentences, the verb is in the indicative mood:

  •   Learning grammar is fun.
  •   Zubin sat beside me.
  •   The tree was felled by the lumberjack.

The verb in the last sentence can be classified as simple past tense, passive voice and indicative mood.
Regardless of tense or voice, an indicative verb states a fact.

Interrogative and Negative

Sometimes an indicative verb must ask a question (interrogative) or make something negative. To do this most
verbs require the auxiliary verb to do:

Interrogative                                 Negative
Do you like Mexican food?           No, I do not like it.
Does he love her?                         No, I do not think so.

In colloquial English we can shorten the negative form to "No I don't," omitting the verb. But this cannot be
done in most other languages. In fact, other languages do not require an auxiliary verb to express interrogatives
and negatives. English has one verb, to be, which does not require the auxiliary:

Are you asleep?                         I am not asleep yet.

The interrogative sentence uses inversion of subject and verb instead; this is common in other languages. The
verb to have can also be used without an auxiliary, but this is becoming rare. For example:

Baa,baa black sheep, have you any wool?
I haven't any money with me.

Imperative

The remaining two moods are used to describe situations which are contrary-to-fact or which have not yet
happened. The imperative mood is the mood of commands or orders:

Get out!                                      Shut up!
Peel me a grape.                         Keep two chevrons apart.

In these sentences, the speaker is issuing an order to the hearer. The action has not yet taken place, but the
speaker demands that it happen. The imperative verb is always addressed to you -- (You) get out! -- so the
subject in English is a second person subject which is hidden or "implied."

Subjunctive

We said above that in an imperative sentence the speaker demands that an action happen. This verb - happen -
is in the third mood, the subjunctive, which is used to show actions or states which are unreal or non-factual,
wished for, required, etc. Here are some examples:

(1) It is necessary that you use a seatbelt.
(2) It is vital that the crime be reported.
(3) If I were rich, I would travel around the world.
(4) They asked that he show up before dinner.
(5) If I had a million dollars, I'd continue to work and invest it all.

There is no distinctive form of the subjunctive in English, and perhaps for this reason many people are unaware
that English possesses this mood at all. It could use the same form as an infinitive, as in (1), (2), and (4), or,
more commonly, the simple past, as in (3) and (5). Notice in (3) that to be becomes were no matter what the
subject is. Verbs in the subjunctive do not change according to person or number.

Sentence (1) reflects obligation but does not state a fact. In (2) the crime has not yet been reported but the
subjunctive shows the importance of that action. Sentences (3) and (5) are hypothetical -- I am not rich, but if I
were (not was), I would travel. The second part of the sentence is conditional -- see below. In sentence (4)
there is a wish for something to happen in the future, but there is no guarantee that it will, in fact, take place;
notice that the verb is show instead of the indicative form shows.

To summarize, let's compare these two sentences:

INDICATIVE:                     He knows that I am there.
SUBJUNCTIVE:                 He demanded that I be there.

While the indicative reflects a true fact, the subjunctive expresses a hypothetical situation. (And of course, with
the imperative "Be there!", the person commanding does not know whether it will happen or not.)

You will encounter the distinct forms of the subjunctive more frequently in other languages than in English, and
its form is usually different from the indicative. In English the subjunctive is often quite indistinguishable from the
simple past, and is therefore sometimes called the unreal past. It is necessary to be able to recognize
subjunctives in English as distinct from simple past forms in order to understand how they work in other
languages. While rules for using the subjunctive may vary slightly from language to language, it is safe to say that
this form of the verb will not usually express known facts but rather wishes, hopes or hypotheses.