SUBJUNCTIVE I (Plain stem of the verb. Denotes a hypothetical action referring to the present or the future.) Used in formulaic expressions to denote wish (Long live Rock 'n' roll!; Success attend you!), concession (So be it!; Come what may) and commands and requests with indefinite pronouns as subjects (Everybody leave the room!).
SUBJUNCTIVE II (Past subjunctive. Expresses unreal actions.) Denotes wish or regret (If only he had come!; Oh, that the rain were over!), preference or advice (We had better get down to work; I would rather study a bit). Can be used with modal verbs. It is followed by an infinitive (Where could we stay for a night?). The non-perfect form is homonymous with the Past Simple, the perfect form is homonymous with the Past Perfect and represents an action which is referred to the past and is contrary to the reality.
THE CONDITIONAL MOOD (The Conditional Mood can be used in simple sentences beginning with "But for…" (But for the rain we should continue our way). It's also used in sentences with implied condition (I wouldn't waste my time on such things in your place). The mood is used by the speaker so as to sound polite (less straightforward) (I should like to speak to her).)The Conditional Mood can be used in simple sentences beginning with "But for…" (But for the rain we should continue our way). It's also used in sentences with implied condition (I wouldn't waste my time on such things in your place). The mood is used by the speaker so as to sound polite (less straightforward) (I should like to speak to her).
THE SUPPOSITIONAL MOOD (Analytical form, built up with the help of the auxiliary verb "should" for all persons + infinitive. Expresses problematic actions (desirable, suggested, required…), which are not necessarily contradict reality. Expresses the same modality as Subjunctive I, that's why they can be used in the same syntactic structure. They are quite interchangeable and differ mainly stylistically.)Used only in interrogative sentences beginning with "What if…" (And what if he should come back?).
The use of the Oblique Moods conditional sentences.
THE CONDITIONAL MOOD
Zero condition (General truth) – used with conjunctions "when, if, unless, provided". One action or result always follows another one (Oil floods if you pour it into water).
Type I – refers to the future (I will help you if you need my help; If I fall in love I will get married).
Type II – the verbs in the oblique moods directly refer to the present or the future (If I could play the guitar, I would be in a rock band).
Type III – the action or the result refer to the past (If I had known of your arrival yesterday I should have met you).
Mixed (split) conditions – a) the present unreal condition and the past unreal result (If I were rich, I would have bought a big house a long time ago); b) the unreal condition refers to the past and the unreal action refers to the present (If he hadn't wasted so much time, he wouldn't be so nervous now).
The use of the Oblique Moods adverbial clauses.
it is used in clauses of concession after "though, although, whatever, etc." (Whatever the reason be, the fact remains) and in clauses of purpose (He stopped talking lest he be offended).
is used in clauses of manner and comparison after the conjunctions "as if, as though" (He spoke as if he were going to cry). It is also used in adverbial clauses of condition (I shouldn't take it if I were you) and in adverbial clauses concession (after "even though") (Even if they had wanted to release the album, it would have been a failure).