{
  "noteId": "preterite-vs-imperfect",
  "target_count": 64,
  "seed_count": 49,
  "generated_count": 15,
  "exercises": [
    {"sentence": "Ayer yo _____ con mi amigo. (hablar)", "correct": "hablé", "distractor": "hablo", "explanation": "Yo preterite of hablar = hablé (with accent)."},
    {"sentence": "Tú _____ una pizza anoche. (comer)", "correct": "comiste", "distractor": "comes", "explanation": "Tú preterite of comer = comiste."},
    {"sentence": "Ella _____ en Madrid el año pasado. (vivir)", "correct": "vivió", "distractor": "vive", "explanation": "Él/ella preterite of vivir = vivió."},
    {"sentence": "Nosotros _____ en el restaurante ayer. (comer)", "correct": "comimos", "distractor": "comamos", "explanation": "Nosotros preterite of comer = comimos."},
    {"sentence": "Ellos _____ todo el día. (trabajar)", "correct": "trabajaron", "distractor": "trabajan", "explanation": "Ellos preterite of trabajar = trabajaron."},
    {"sentence": "Yo _____ tres millas esta mañana. (correr)", "correct": "corrí", "distractor": "corro", "explanation": "Yo preterite of correr = corrí."},
    {"sentence": "Tú _____ la carta. (escribir)", "correct": "escribiste", "distractor": "escribes", "explanation": "Tú preterite of escribir = escribiste."},
    {"sentence": "Ayer yo _____ al cine.", "correct": "fui", "distractor": "iba", "explanation": "Preterite of ir = fui (completed action). 'Iba' is imperfect."},
    {"sentence": "La fiesta _____ muy divertida.", "correct": "fue", "distractor": "era", "explanation": "An event that happened — use the preterite of ser (fue)."},
    {"sentence": "Nosotros _____ a la playa el sábado.", "correct": "fuimos", "distractor": "vamos", "explanation": "Preterite of ir = fuimos. 'Vamos' is present."},
    {"sentence": "Tú _____ doctor antes, ¿verdad?", "correct": "fuiste", "distractor": "fue", "explanation": "Tú preterite of ser = fuiste."},
    {"sentence": "Ellos _____ al supermercado anoche.", "correct": "fueron", "distractor": "fueran", "explanation": "Preterite of ir, ellos form = fueron."},
    {"sentence": "_____ difícil aprender español.", "correct": "Fue", "distractor": "Era", "explanation": "Completed evaluation of an event — preterite of ser (fue)."},
    {"sentence": "¿A dónde _____ tú anoche?", "correct": "fuiste", "distractor": "fueras", "explanation": "Preterite of ir, tú form = fuiste."},
    {"sentence": "Ayer yo _____ que trabajar mucho. (tener)", "correct": "tuve", "distractor": "tení", "explanation": "Preterite of tener uses tuv- stem: tuve."},
    {"sentence": "Nosotros _____ en la playa el verano pasado. (estar)", "correct": "estuvimos", "distractor": "estábamos", "explanation": "Preterite of estar uses estuv-: estuvimos. 'Estábamos' is imperfect."},
    {"sentence": "Yo _____ las llaves en la mesa. (poner)", "correct": "puse", "distractor": "ponía", "explanation": "Preterite of poner uses pus-: puse."},
    {"sentence": "Ellos me _____ la verdad. (decir)", "correct": "dijeron", "distractor": "dijieron", "explanation": "j-stem verbs take -eron, not -ieron: dijeron."},
    {"sentence": "¿Qué _____ tú anoche? (hacer)", "correct": "hiciste", "distractor": "hizo", "explanation": "Tú preterite of hacer = hiciste."},
    {"sentence": "Ella _____ un pastel para mi cumpleaños. (hacer)", "correct": "hizo", "distractor": "hico", "explanation": "Él/ella form of hacer is hizo (with z) to preserve the soft sound."},
    {"sentence": "Yo _____ tarde a la fiesta. (venir)", "correct": "vine", "distractor": "vení", "explanation": "Preterite of venir uses vin-: vine."},
    {"sentence": "Nosotros _____ comida a la fiesta. (traer)", "correct": "trajimos", "distractor": "traímos", "explanation": "Preterite of traer uses traj-: trajimos."},
    {"sentence": "Tú _____ el coche al taller. (conducir)", "correct": "condujiste", "distractor": "conduciste", "explanation": "Preterite of conducir uses conduj-: condujiste."},
    {"sentence": "Yo no _____ ir a la fiesta. (poder)", "correct": "pude", "distractor": "podía", "explanation": "Preterite poder = pude (managed to / could). 'Podía' is imperfect."},
    {"sentence": "Ayer yo _____ que estás casado. (saber)", "correct": "supe", "distractor": "sabía", "explanation": "Preterite saber = supe and means 'I found out'. 'Sabía' = 'I knew (already)'."},
    {"sentence": "Ellos _____ ocho horas anoche. (dormir)", "correct": "durmieron", "distractor": "dormieron", "explanation": "dormir is a 3rd-person stem-changer: o→u in ellos: durmieron."},
    {"sentence": "Ella _____ una hamburguesa. (pedir)", "correct": "pidió", "distractor": "pedió", "explanation": "pedir is a 3rd-person stem-changer: e→i in él/ella: pidió."},
    {"sentence": "Yo _____ a mi amigo en la calle. (ver)", "correct": "vi", "distractor": "ví", "explanation": "Preterite ver = vi (no written accent)."},
    {"sentence": "Yo te _____ un regalo. (dar)", "correct": "di", "distractor": "dí", "explanation": "Preterite dar = di (no written accent)."},
    {"sentence": "Él _____ el periódico esta mañana. (leer)", "correct": "leyó", "distractor": "leió", "explanation": "leer takes y in 3rd person: leyó."},
    {"sentence": "Yo _____ al tenis ayer. (jugar)", "correct": "jugué", "distractor": "jugé", "explanation": "-gar verbs change yo to -gué: jugué."},
    {"sentence": "Yo _____ español por dos horas. (practicar)", "correct": "practiqué", "distractor": "practicé", "explanation": "-car verbs change yo to -qué: practiqué."},
    {"sentence": "Yo _____ a estudiar a las ocho. (empezar)", "correct": "empecé", "distractor": "empezé", "explanation": "-zar verbs change yo to -cé: empecé."},
    {"sentence": "Cuando era niño, _____ al parque todos los días.", "correct": "iba", "distractor": "fui", "explanation": "Habitual past action → imperfect of ir."},
    {"sentence": "Mientras yo _____, sonó el teléfono.", "correct": "comía", "distractor": "comí", "explanation": "Background ongoing action → imperfect."},
    {"sentence": "Cuando éramos jóvenes, nosotros _____ en Madrid.", "correct": "vivíamos", "distractor": "vivimos", "explanation": "Habitual past → imperfect of vivir."},
    {"sentence": "_____ las cinco cuando llegó.", "correct": "Eran", "distractor": "Fueron", "explanation": "Time in the past always uses imperfect of ser."},
    {"sentence": "Mi abuela _____ mucho la tele.", "correct": "veía", "distractor": "vio", "explanation": "Habit → imperfect of ver."},
    {"sentence": "Yo _____ hablando cuando entró.", "correct": "estaba", "distractor": "estuve", "explanation": "Past progressive needs estar in the imperfect."},
    {"sentence": "Él _____ muy alto de joven.", "correct": "era", "distractor": "fue", "explanation": "Trait/description → imperfect of ser."},
    {"sentence": "Tú siempre _____ pan en la panadería.", "correct": "comprabas", "distractor": "compraste", "explanation": "'Siempre' + habitual action → imperfect."},
    {"sentence": "Ella ya _____ salido. (haber)", "correct": "había", "distractor": "ha", "explanation": "Past perfect uses imperfect haber 'había'."},
    {"sentence": "Yo ya _____ estudiado.", "correct": "había", "distractor": "habría", "explanation": "Yo form is 'había' in imperfect."},
    {"sentence": "Nosotros _____ visto la película.", "correct": "habíamos", "distractor": "hemos", "explanation": "Nosotros form 'habíamos' for past perfect."},
    {"sentence": "Antes de llegar, yo ya _____ comido.", "correct": "había", "distractor": "he", "explanation": "Past perfect with antes de."},
    {"sentence": "Él no me lo _____ mostrado.", "correct": "había", "distractor": "habrá", "explanation": "Negation goes before haber, which stays imperfect."},
    {"sentence": "I had a dog (state) → Yo _____ un perro.", "correct": "tenía", "distractor": "había tenido", "explanation": "Ongoing past state uses imperfect of tener."},
    {"sentence": "I had to study → Yo _____ que estudiar.", "correct": "tuve", "distractor": "había", "explanation": "Completed obligation uses preterite of tener."},
    {"sentence": "Antes de ir al trabajo, me _____ duchado.", "correct": "había", "distractor": "habíamos", "explanation": "Reflexive 'me' before haber, yo form 'había'."},
    {"sentence": "Anoche yo _____ una película muy buena. (ver)", "correct": "vi", "distractor": "veía", "explanation": "Completed event last night → preterite of ver."},
    {"sentence": "Cuando yo _____ joven, jugaba al fútbol.", "correct": "era", "distractor": "fui", "explanation": "Description in the past → imperfect of ser."},
    {"sentence": "Ellos _____ el coche cuando empezó a llover.", "correct": "lavaban", "distractor": "lavaron", "explanation": "Ongoing background action → imperfect."},
    {"sentence": "Yo _____ la tarea cuando llegó mi madre.", "correct": "hacía", "distractor": "hice", "explanation": "Action in progress interrupted by another → imperfect."},
    {"sentence": "Ayer mi padre me _____ cien dólares. (dar)", "correct": "dio", "distractor": "daba", "explanation": "Single completed event → preterite of dar."},
    {"sentence": "El concierto _____ fantástico anoche.", "correct": "fue", "distractor": "era", "explanation": "Completed event evaluation → preterite of ser."},
    {"sentence": "Todos los domingos nosotros _____ a misa.", "correct": "íbamos", "distractor": "fuimos", "explanation": "'Todos los domingos' = habitual → imperfect of ir."},
    {"sentence": "De repente, yo _____ un ruido extraño. (oír)", "correct": "oí", "distractor": "oía", "explanation": "'De repente' signals a sudden completed action → preterite."},
    {"sentence": "Ella _____ cansada después del partido.", "correct": "estaba", "distractor": "estuvo", "explanation": "Description of state → imperfect of estar."},
    {"sentence": "Mi hermano _____ tres veces a España.", "correct": "viajó", "distractor": "viajaba", "explanation": "Specific number of completed times → preterite."},
    {"sentence": "Cada verano nosotros _____ a la playa.", "correct": "íbamos", "distractor": "fuimos", "explanation": "'Cada verano' = habitual → imperfect."},
    {"sentence": "Él _____ la puerta y entró sin mirar.", "correct": "abrió", "distractor": "abría", "explanation": "Sequence of completed actions → preterite."},
    {"sentence": "Mientras ella leía, su hijo _____. (dormir)", "correct": "dormía", "distractor": "durmió", "explanation": "Two simultaneous ongoing actions → both imperfect."},
    {"sentence": "Cuando _____ cinco años, vivía en México.", "correct": "tenía", "distractor": "tuve", "explanation": "Age in the past → imperfect of tener."},
    {"sentence": "El año pasado yo _____ a Italia. (ir)", "correct": "fui", "distractor": "iba", "explanation": "Specific completed trip → preterite of ir."},
    {"sentence": "Yo _____ la película tres veces el mes pasado.", "correct": "vi", "distractor": "veía", "explanation": "Specific completed count → preterite of ver."}
  ]
}
