From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.

Given Relationship: 'be island in', Sentence: 'Cuba is the bigger island extension of the biggest Antilles .'
island

Given Relationship: 'be service of', Sentence: 'See a list of publications by Mayo Clinic authors on mitral valve disease on PubMed , a service of the National Library of Medicine .'
service

Given Relationship: 'be speak in', Sentence: 'Hong Kong speaks Cantonese , which is a dialect of Mandarin and has a different spoken syntax .'

speaks