Mood, or mode, is a term applied to verb forms that distinguish among certain kinds of meaning. For example, the verb is in “He is my brother” is an indicative mood form—that is, it states a fact. But the verb were in “if he were my brother” is a subjunctive mood form—that is, it expresses a condition contrary to fact.
Some languages have elaborate mood forms, but in English not many contrasts remain between the indicative and the subjunctive mood. For the verb be, the indicative forms of the present tense are I am, you are, he is, we are, and they are. The subjunctive forms are I be, you be, he be, we be, and they be. In the past tense, the indicative forms are I was, you were, he was, we were, and they were, and the subjunctive forms are I were, you were, he were, we were, and they were. Other verbs have a distinction at only one point: the third person singular of the present tense. For instance, she calls is indicative, but she call is subjunctive.
Subjunctive uses.
Although the subjunctive has limited forms and uses in English, it is useful as a way of expressing a wish, a request, urgency, or a condition contrary to fact:
I wish it were true. (wish) She asked that we be admitted. (request) It is necessary that he stay. (urgency) If words were deeds, we would be finished. (condition contrary to fact)
Older English usage employed the present subjunctive frequently in clauses introduced by if and though, such as “If it be he, let him be admitted,” and “Though she call repeatedly, I shall not answer.”
Other older uses of the subjunctive survive in many expressions, most of which are blessings or prayerful wishes: God bless you, Long live the king, Heaven forbid, Suffice it to say, and God be with you.
Imperative mood.
The term imperative mood is commonly given to verbs that express commands or requests. “Stop the music,” “Leave the room,” and “Give this to your mother” are some examples. In English, the imperative form is the base (simple) form of the verb. Imperative sentences usually have no subjects, and the omission of the subject is one of the chief signals that the sentence is a command or a request. But sometimes, imperative sentences do have subjects, as in “You do it, George.”
Verb phrases.
The terms mood and mode are also applied sometimes to verb phrases like might go, should stay, and may try. Words like may, might, should, and would are often called modal auxiliaries. They express the same meanings conveyed by mood endings on the verb in such languages as Greek or Latin. In English, however, modern grammarians usually limit the term mood to the indicative, subjunctive, and imperative forms, omitting the modals.
