Since you didn't

At its core, the imperfect subjunctive is the past-tense partner of the present subjunctive. If you say Quiero que vayas (I want you to go) in the present, you’ll need the imperfect to say Quería que fueras (I wanted you to go) in the past. It’s all about maintaining that "subjunctive mood"—the realm of the non-factual. It covers actions that were subjective, uncertain, or dependent on someone else's will. It’s also the magic ingredient for "Si" (if) clauses that deal with things that aren't true right now. For example, if you're stuck in an office and dream of being on a beach, you'd use this tense. It’s a bit like a time-traveling emotional filter for your sentences.

1. 1This is where it gets a little quirky. You don’t build this tense from the infinitive. Instead, you have to go through the "Ellos/Ustedes" form of the Preterite (Simple Past). It’s a bit of a detour, but it ensures that all those nasty irregular preterites (like hicieron or tuvieron) stay consistent.
2. 2Start with the 3rd person plural (ellos/ellas/ustedes) of the Preterite. For hablar, that’s hablaron.
3. 3Chop off the -ron ending. You’re left with the root: habla-.
4. 4Add the Imperfect Subjunctive endings. There are actually two sets: the -ra set (more common) and the -se set (mostly used in Spain or formal writing). We'll focus on the -ra set here.
5. 5Endings for -ra set:
6. 6yo: -ra
7. 7tú: -ras
8. 8él/ella/usted: -ra
9. 9nosotros: -ramos (Note: Always add an accent on the vowel before the ending! habláramos)
10. 10vosotros: -rais
11. 11ellos/ellas/ustedes: -ran
12. 12Example for tener (Preterite ellos: tuvieron):
13. 13tuviera, tuvieras, tuviera, tuviéramos, tuvierais, tuvieran.

1. 1Past Requests and Desires: When you wanted someone to do something. Mi jefe me pidió que trabajara el sábado. (My boss asked me to work Saturday). No one likes that guy, right?
2. 2Hypothetical "If" Situations: Paired with the conditional. Si fuera rico, compraría un barco. (If I were rich, I’d buy a boat). This is the classic "dreaming" structure.
3. 3Polite Requests: Using quisiera (I would like) instead of quiero (I want) makes you sound 100% more sophisticated at a job interview or ordering food. Quisiera una mesa para dos, por favor.
4. 4Past Emotions: Expressing how you felt about something that happened. Me molestó que no vinieras. (It bothered me that you didn't come).
5. 5Unknown Situations: Searching for something that might not exist in the past. Buscaba un hotel que tuviera piscina. (I was looking for a hotel that had a pool).

1. 1Facts and Certainty: If it actually happened and you're just stating a fact, stay in the Indicative (Preterite or Imperfect). Sabía que ella estaba en casa. (I knew she was at home).
2. 2Present Reality: If the trigger is in the present and it's a real possibility, use the present subjunctive. Espero que vengas (I hope you come) vs Esperaba que vinieras (I hoped you'd come).
3. 3After "Si" for Real Things: Don't use it if the condition is likely. Si tengo tiempo, iré. (If I have time, I'll go). Only use it for the "imaginary" stuff.

• The "Si" Clause Swap: A very common error is using the Conditional after si. Never say Si tendría dinero... ✗. Always say Si tuviera dinero... ✓. It’s a total giveaway that you’re a learner (though some natives do it too, don't be that person!).
• Forgetting the Accent: In the nosotros form, you absolutely need that accent. Habláramos, tuviéramos. Without it, the rhythm of the language just feels "off."
• Using the wrong root: You must use the Preterite ellos form. For leer, the preterite is leyeron, so the subjunctive is leyera, not leiera. It’s like a secret handshake; you have to know the preterite to get in.

• vs. Present Subjunctive: Es posible que llueva (It might rain today) vs Era posible que lloviera (It might have rained yesterday). The mood is the same, just the timeline shifts.
• vs. Conditional: They are best friends in "Si" clauses. Subjunctive sets the imaginary scene (Si fuera...), and Conditional describes the result (...compraría). Think of the subjunctive as the "setup" and the conditional as the "payoff."