The category of Mood is the most controversial category of the verb.
B.A. Ilyish: " The category of mood in the present English verb has given rise to so many discussions, and has been treated in so many different ways, that it seems hardly possible to arrive at any more less convincing and universally acceptable conclusion concerning it."
Among the scholars to be named in the first place in relation to the problem are A.I. Smirnitsky, whose theories revolutionized the presentation of English verbal grammar; then B.A. Ilyish , a linguist who made a great contribution to the general problem of mood; then Y.N. Vorontsova; Z.S. Khlebnikova.
The category of Mood expresses the relations between the action, denoted by the verb, and the actual reality from the point of view of the speaker. The speaker may treat the action/event as real, unreal or problematic or as fact that really happened, happens or will happen, or as an imaginary phenomenon.
It follows from this that the category of Mood may be presented by the opposition
obligue mood - direct mood
= unreality = reality.
The former is the strong member.
The latter is the weak member.
Mood relates the verbal action to such conditions as certainty, obligation, necessity, possibility.
The most disputable question in the category of mood is the problem of number and types of Obligue Moods. Obligue Moods denote unreal or problematic actions so they can't be modified by the category of tense proper. They denote only relative time, that is simultaneousness or priority. Due to the variety of forms it's impossible to make up regular paradigms of Obligue Moods and so classify them.
Some authors pay more attention to the plane of expression, other to the plane of content. So different authors speak of different number and types of moods. The most popular in Grammar has become the system of moods put forward By Prof. Smirnitsky. He speaks of 6 mood forms:
The Indicative Mood
The Imperative Mood
The Conditional Mood
The Suppositional Mood
Subjunctive I expresses a problematic action. Subjunctive I is used in American English and in newspaper style. Subjunctive I coincides with the Infinitive without the particle to. Ex.: Ring me up if he would be there.
This mood is expressed in English to a very minor extent (e.g.: So be it then!). It is only used in certain set expressions, which have to be learned as wholes:
Come what may, we will go ahead.
God save the Queen!
Suffice it to say that...
Be that as it may...
Heaven forbid that...
So be it then.
Long live the King!
Grammar be hanged!
This Mood is also used in that clauses, when the main clause contains an expression of recommendation, resolution, demand, etc. The use of this subjunctive I occurs chiefly in formal style (and especially in Am E) where in less other devices, such as to - infinitive or should = infinitive.
It is necessary that he be there.
It is necessary that he should be there.
It is necessary for him to be there.
Subjunctive II denotes an unreal action and it coincides in the form with the Past Indefinite Tense (Subjunctive II Present) or Past Perfect (Subjunctive II Past). Ex.: I wish he had told the truth. If only he were here!
Mood is expressed in English to a much greater extent by past tense forms. E.g.:
If you taught me, I would learn quickly.
If she was/were to do smth like that.
He spoke to me as if I was/ were deaf...
I wish I was/were was
1) “Was” is more common in less formal style
2) Only “were” is acceptable in "As it were" (= so to speak)
3) “Were” is usual in "If I were you".
The Conditional Mood denotes an unreal action and is built by the auxiliary verb "world" + any Infinitive a non-perfect infinitive expresses Simultaneousness while a perfect infinitive expresses priority. E.g.: But for the rain we would go for a walk. But for the rain we would have gone...
The Suppositional Mood also expresses a problematic action and is formed with the help of the auxiliary verb "should" for all the persons + Infinitive. E.g.: Ring me up if he should be there.
This mood can be used with any verb in subordinate that - clauses when the main clause contains an expression of recommendation resolution, demand etc. (demand, require, insist, suggest...) E.g.: It is necessary that every member should inform himself of these rules = It is necessary for every member to inform... It is strange that he should have left so early.
Subjunctive I and the Suppositional Mood are differentiated only by their form but their meaning is the same.
Taking into consideration the fact that the forms of the Obligue Moods coincide in many cases with the forms of the Indicative Mood, there arises a problem of homonymy or polysemy. E.g.: He lived here. (The indicative Mood, Past Tense, Priority, real action).