[
  {
    "sentence": "_____ libro es interesante. (this)",
    "correct": "Este",
    "distractor": "Esta",
    "explanation": "Libro is masculine singular → este.",
    "source_chapter": "10",
    "source_title": "Demonstrative Adjectives"
  },
  {
    "sentence": "_____ casas son grandes. (these)",
    "correct": "Estas",
    "distractor": "Estos",
    "explanation": "Casas is feminine plural → estas.",
    "source_chapter": "10",
    "source_title": "Demonstrative Adjectives"
  },
  {
    "sentence": "_____ cursos son difíciles. (those)",
    "correct": "Esos",
    "distractor": "Eses",
    "explanation": "Masculine plural of ese is esos, not 'eses'.",
    "source_chapter": "10",
    "source_title": "Demonstrative Adjectives"
  },
  {
    "sentence": "¿Qué es _____? (this — unknown)",
    "correct": "esto",
    "distractor": "este",
    "explanation": "Use neuter esto when the thing's gender is unknown.",
    "source_chapter": "10",
    "source_title": "Demonstrative Adjectives"
  },
  {
    "sentence": "_____ es para todos. (that — general)",
    "correct": "Eso",
    "distractor": "Ese",
    "explanation": "General/abstract → neuter eso.",
    "source_chapter": "10",
    "source_title": "Demonstrative Adjectives"
  },
  {
    "sentence": "_____ mesa (that, f sg).",
    "correct": "Esa",
    "distractor": "Esta",
    "explanation": "Mesa is feminine singular and 'that' (near listener) is esa.",
    "source_chapter": "10",
    "source_title": "Demonstrative Adjectives"
  }
]