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: 'join', Sentence: 'Turkey 's effort to join the European Union has already been an up and down affair .'
join

Given Relationship: 'land on', Sentence: 'Huygens - landed on Titan , Saturn 's largest moon , in January 2005 .'
landed

Given Relationship: 'use on', Sentence: 'The Domain Name System used by the Internet .'

used