Question: Which reservoir has the largest volume?
Paraphrase: what is the reservoir with the largest volume of water?
SPARQL (Wikidata): select ?ent where { ?ent wdt:P31 wd:Q131681 . ?ent wdt:P2234 ?obj } ORDER BY DESC(?obj)LIMIT 5 
Answer: Kielder Water, Kielder Water, Överuman, Storavan, Stora Lulevatten