Past subjunctive

The past subjunctive has the same form as the past simple tense except in the case of the verb be. Traditionally, the past subjunctive form of be is were for all persons, including the first and third person singular. However, today I/he/she/it was is more common while were is mainly used in formal styles and in the set phrase if I were you.

The past subjunctive is used in subordinate clauses and refers to unreal or improbable present or future situations: 

If I were you, I would apply right now. (I am not you.)
What would you do if you won the lottery? (You probably won't win the lottery.)
It's time the kids were in bed. (The kids are not in bed.)
I wish you were here. (You are not here.)
I'd rather your boyfriend stopped calling you in the middle of the night. (Your boyfriend keeps calling you.)
He looks as if he knew the answer. (He gives the impression that he knows the answer, but he probably doesn't.)