The Subjunctive Mood
There are two forms: the past and the present subjunctive. Their use relates to mood rather than tense. Where the clause has a plural subject there is no difference between the indicative and subjunctive forms: I insist that we reconsider the council’s decisions. BUT I insist that the council reconsider its decisions or I insist that the council’s decisions be reconsidered. In the firs case it can be both indicative or subjunctive, but in the last two cases it is subjuntive.
In case of past subjunctive it is no matter what form the verb be takes on in indicative the past form will always be were. If he were leaving, you would have heard about it.
A passive subjunctive is a possibility for the mandative and the formulaic subjunctive as well. In case of the verb be, not may be placed before or after the verb. It is essential that this mission not fail.
The Mandative Subjunctive
This is the most common use. Occurs in subordinate that clauses and consists of the base form of the verb. The present and past forms are indistinguishable: The commitee proposes(ed)(that) Mr Smith be elected. That clause with mandative subjunctive can be introduced by verbs suc as: decide, insist, move, order, prefer, request. Adjectives: advisable, desirable, fitting, imperative. Nouns: decision, decree, order, requirement, resolution. The mandative is more characteristic in AmE, where it is formal. BrE: The employees demanded that the manager should resign/resigns. In AmE: /resign.
The Formulaic Subjunctive
Like the latter it consists of the base form of the verb, but it is used in certain expressions chiefly in independent clauses. Come what may/God save the Queen/Suffice it to say/Heaven forbid that/ Be it notted that/Be that as it may….. (tegyünk úgy mintha).
Other uses of the present subjunctive:
In clauses of condition and concession: Even if that be the official view, it cannot be accepted.
Clauses of condition or negative purpose introduced by lest or for fear that.
The president must reject this proposal, lest it cause strife and violence.
The were subjunctive:
It is unreal in meaning, being used in adverbial clauses introduced by such conjunctions as: if, as if, as though, though, and in nominal clauses after verbs like wish and suppose. We only use were in these cases. Though in less formal style was is also permitted.:
If I were rich, I would buy you anything you wanted. I wish the journey were over. Just suppose everyone were to give up smoking and drinking. It is less usual nowadays.