Question: : What are the family of isomeric compounds which start with the letter x
Paraphrase: : What are the family of isomeric compounds which begin with the letter x
SPARQL (Wikidata): SELECT DISTINCT ?sbj ?sbj_label WHERE { ?sbj wdt:P31 wd:Q15711994 . ?sbj rdfs:label ?sbj_label . FILTER(STRSTARTS(lcase(?sbj_label), 'x')) . FILTER (lang(?sbj_label) = 'en') } LIMIT 25 
Answer: xylene, xylene, xylidine, xylidine, xylenol, xylenol, xylose, xylose