[
  {
    "sentence": "Yo voy _____ baño.",
    "correct": "al",
    "distractor": "a el",
    "explanation": "a + el always contracts to al.",
    "source_chapter": "15",
    "source_title": "al & del"
  },
  {
    "sentence": "Vengo _____ mercado.",
    "correct": "del",
    "distractor": "de el",
    "explanation": "de + el always contracts to del.",
    "source_chapter": "15",
    "source_title": "al & del"
  },
  {
    "sentence": "Quiero ir _____ clase.",
    "correct": "a la",
    "distractor": "al",
    "explanation": "Feminine la does not contract.",
    "source_chapter": "15",
    "source_title": "al & del"
  },
  {
    "sentence": "Es el regalo _____ profesor.",
    "correct": "del",
    "distractor": "de la",
    "explanation": "Profesor is masculine, so de + el = del.",
    "source_chapter": "15",
    "source_title": "al & del"
  },
  {
    "sentence": "El libro es _____ él.",
    "correct": "de",
    "distractor": "del",
    "explanation": "The pronoun él (with accent) does not contract; only the article el does.",
    "source_chapter": "15",
    "source_title": "al & del"
  },
  {
    "sentence": "Vamos _____ playa.",
    "correct": "a la",
    "distractor": "al",
    "explanation": "Playa is feminine; no contraction.",
    "source_chapter": "15",
    "source_title": "al & del"
  },
  {
    "sentence": "El presidente _____ Salvador habló.",
    "correct": "de El",
    "distractor": "del",
    "explanation": "Proper nouns with capital El don't contract.",
    "source_chapter": "15",
    "source_title": "al & del"
  }
]