It is difficult for english-speaking people to learn the tenses. Keep on studying!
Subjunctive is not one of the most common tenses in spanish. It is usually used in conditional sentences as english subjunctive. For example:
If I had a job, I could buy a car. (Si tuviera...)
I would have bought a car if I have had money at the time. (Hubiera comprado un coche si hubiera tenido dinero en ese momento).
If I were you I will buy the damned car! (¡Si yo fuera tú compraría el maldito coche!)
You see, easy to use, hard to learn
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