Президенте Республики Беларусь Система открытого образования Практическая грамматика английского языка для среднего и продвинутого

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  the Indicative Mood,
  
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  the Imperative Mood, and
  
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  the Subjunctive Mood.
  

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  in that-clauses expressing resolution, recommendation, command or necessity (the Present Subjunctive):
  

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  in if-clauses and after the verb to wish (see Unit 7) to denote an unreal condition referring to the present or future or to the past if the verb in the if-clause expresses an action simultaneous with the action in the principal clause (the Past Subjunctive):
  

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  in conditional sentences both in the subordinate clause (if-clause) to express an unreal condition, and in the principal (main) clause to express an unreal consequence (see Units 2-6):
  

1) If she were here, you would notice him. (The Past Subjunctive)

Если бы она была здесь, она бы заметила его

2) If we had had a rope, we could have saved him. (The Perfect

Если бы у нас (тогда) был канат, Subjunctive)

мы бы спасли его

the if-clause the main clause