The subjunctive mood in English is a form verb expressing desire, conjecture, doubt or the unreality of the action. In Russian it is expressed verbs in the past tense in combination with the particle "would" (so that if would, etc.)
If I were there I should ring you up. Если бы я был там, я бы позвонил тебе. I wish she would win the game. Мне бы хотелось, чтобы она выиграла игру. If I knew her address we should write to her. Если бы я знал её адрес, мы бы написали ей.
The subjunctive mood Subjunctive I (synthetic form) is used in a simple sentence and in the main and subordinate clauses of a complex sentence (in the main - with a conditional clause expressing an unrealistic condition). The subjunctive mood Subjunctive II (analytical form) is used in the subordinate clause of a complex sentence.