Mood

Mood is the use of form to indicate semantic and grammatical differences in the manner of the action of a verb. Three moods are used in English.

Indicative mood is used to state a fact or ask a question:

What is the moon made of? The moon is made of blue cheese.

Imperative mood is used to issue a command or make a request:

Eat your moon. Please pass the cheese.

Subjunctive mood is used to express doubt, wishing, belief, or improbability:

If the moon were made of blue cheese, it would smell.

The subjunctive mood is indicated through a shift in tense when the dependent clause follows a wish statement, or is an improbable if clause.

Indicative:

I know the time. [present]

Subjunctive:

I wish I knew the time. [past]

Probable if clause:

If I buy a watch I will know the time.

Improbable:

If I won the lottery, I would not care about the time.

Sentences that express urging, demand, or necessity also require the subjunctive mood. Verbs other than the verb 'to be' in the dependent clause use the present tense form of the verb, without adding the 's' for the third person singular:

I demand that she apologize to the student.

Such sentences that require the verb 'to be' in the dependent clause use the form 'be' in all three persons:

I insist that I be promoted.

I had insisted that you be hired immediately.

They insisted that she be nominated for President.