{
  "chapter_id": "10",
  "slug": "demonstrative-adjectives",
  "title": "Demonstrative Adjectives",
  "time_range_sec": [2312, 2450],
  "summary": "Spanish demonstratives (este/ese/aquel) precede the noun and agree in gender and number. Neuter forms (esto/eso/aquello) refer to unidentified or general ideas.",
  "suggested_grammar_note_id": null,
  "rules": [
    {
      "title": "Three distances",
      "bullets": [
        "este/esta = this (near the speaker).",
        "ese/esa = that (near the listener).",
        "aquel/aquella = that one over there (far from both)."
      ]
    },
    {
      "title": "Agreement and pluralization",
      "bullets": [
        "Demonstratives agree in gender and number with the noun.",
        "Masculine plural changes vowel: este → estos, ese → esos, aquel → aquellos.",
        "Feminine plural simply adds -s: esta → estas, esa → esas."
      ]
    },
    {
      "title": "Neuter forms",
      "bullets": [
        "Use esto, eso, aquello when the thing has no known gender or for abstract ideas.",
        "Examples: ¿Qué es esto? / Esto es para todos."
      ]
    },
    {
      "title": "Don't accent esta/estas",
      "bullets": [
        "esta = this (f); está = he/she/it is.",
        "estas = these (f); estás = you are."
      ]
    }
  ],
  "examples": [
    {"es": "este libro", "en": "this book", "tags": ["masculine", "singular"]},
    {"es": "esta casa", "en": "this house", "tags": ["feminine", "singular"]},
    {"es": "ese curso", "en": "that course", "tags": ["masculine", "singular"]},
    {"es": "esa mesa", "en": "that table", "tags": ["feminine", "singular"]},
    {"es": "estos libros", "en": "these books", "tags": ["masculine", "plural"]},
    {"es": "estas casas", "en": "these houses", "tags": ["feminine", "plural"]},
    {"es": "esos cursos", "en": "those courses", "tags": ["masculine", "plural"]},
    {"es": "esas mesas", "en": "those tables", "tags": ["feminine", "plural"]},
    {"es": "¿Qué es esto?", "en": "What is this?", "tags": ["neuter"]},
    {"es": "¿Qué es eso?", "en": "What is that?", "tags": ["neuter"]},
    {"es": "Esto es para todos.", "en": "This is for everybody.", "tags": ["neuter", "general"]},
    {"es": "Eso es para todos.", "en": "That is for everybody.", "tags": ["neuter", "general"]},
    {"es": "aquel libro", "en": "that book (over there)", "tags": ["far"]},
    {"es": "aquellas mesas", "en": "those tables (over there)", "tags": ["far", "plural"]}
  ],
  "vocab": [
    {"es": "este / esta / estos / estas", "en": "this / these", "pos": "adj"},
    {"es": "ese / esa / esos / esas", "en": "that / those", "pos": "adj"},
    {"es": "aquel / aquella / aquellos / aquellas", "en": "that / those (over there)", "pos": "adj"},
    {"es": "esto / eso / aquello", "en": "this / that / that (neuter)", "pos": "adj"},
    {"es": "libro", "en": "book", "pos": "noun"},
    {"es": "casa", "en": "house", "pos": "noun"},
    {"es": "curso", "en": "course", "pos": "noun"},
    {"es": "mesa", "en": "table", "pos": "noun"}
  ],
  "conjugation_tables": [],
  "exercises": [
    {"sentence": "_____ libro es interesante. (this)", "correct": "Este", "distractor": "Esta", "explanation": "Libro is masculine singular → este."},
    {"sentence": "_____ casas son grandes. (these)", "correct": "Estas", "distractor": "Estos", "explanation": "Casas is feminine plural → estas."},
    {"sentence": "_____ cursos son difíciles. (those)", "correct": "Esos", "distractor": "Eses", "explanation": "Masculine plural of ese is esos, not 'eses'."},
    {"sentence": "¿Qué es _____? (this — unknown)", "correct": "esto", "distractor": "este", "explanation": "Use neuter esto when the thing's gender is unknown."},
    {"sentence": "_____ es para todos. (that — general)", "correct": "Eso", "distractor": "Ese", "explanation": "General/abstract → neuter eso."},
    {"sentence": "_____ mesa (that, f sg).", "correct": "Esa", "distractor": "Esta", "explanation": "Mesa is feminine singular and 'that' (near listener) is esa."}
  ],
  "caveats": "OCR introduced 'AEL' / 'AOS' artifacts; cleaned to aquel/aquellos."
}