There are three ways of expressing the Subjunctive mood - synthetic forms, analytical forms and some forms of the Indicative mood used in the meaning of the Subjunctive mood.

Synthetic forms were widely spread in Old English where different forms have different flexions. But in cause of time most of those flexions were lost. So that in Modern English there are but two synthetic forms of the Subjunctive mood - the Present Subjunctive of all verbs and the Past Subjunctive of the verb to be.

The Present Subjunctive is the first form of the verb (the Infinitive without the particle to) for all persons singular and plural.

Singular Plural
1 I be (write) We be (write)
2 You be (write) You be (write)
3 He, she, it be (write) They be (write)

The Past Subjunctive of the verb to be has the form were for all persons singular and plural.

The Present Subjunctive is but seldom used in modern colloquial English. It is mostly used in the language of official documents such as International treats, in poetry, in elevated prose and in some set-expressions:

Be he generous, wise and brave
He will only be a slave.

Если бы он был щедрым, мудрым и храбрым
Он был бы просто рабом.

Long live the King!
Да здравствует король!

Be it so!
Да будет так!

Far be it from me to contradict you!
Да у меня и в мыслях нет противоречить вам.

God bless you!
Будь здоров!

God Bless America!
Боже, храни Америку!

Fuck you.
Чтоб тебя.

But in American English the Present Subjunctive is widely used in colloquial speech.

She insisted that they drink to her health.
Она настояла на том, чтобы они выпили за ее здоровье.

The Past Subjunctive is widely used in colloquial speech both in British and in American English. For example: in the subordinate clause of conditional sentences.

The term Past Subjunctive is merely traditional and does not mean that the action refers to the past. In the contrary in some models, it denotes an action referring to the present or future in other models - an action is the simultaneous with the action in the principal clause.

If he were here now, he would help us.
Если ли бы он был здесь сейчас, он бы помог нам.

I wish she were not married.
Жаль, что она замужем.

He wished she were not married.
Хотел бы он, чтобы она не была замужем.

The analytical forms of the Subjunctive mood consist of the mood auxiliaries: should, would, may, might plus the bare Infinitive of the notional verb.

If he joined them, they would do this work easier.
Если бы он присоединился к ним, они бы сделали эту работу быстрее.

However interesting this program might be, we cannot discuss it now.
Какой бы интересной не была эта программа, мы не можем обсуждать ее сейчас.

The forms of the Indicative mood used in the meaning of the Subjunctive mood are the Past Indefinite and the Past Perfect (the Past Continuous and the Past Perfect Continuous - also occur here).

If he had money now, he would buy my Opel.
Если бы у него были сейчас деньги, он бы купил мой опель.

If he had had money, he would have bought my Opel.
Если бы у него тогда были деньги, он бы купил мой опель.