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.

[EX Q]: Given Relationship: 'declare war on', Sentence: 'When the United States declared war on Germany on April 6 , 1917 , Hemingway tried to enlist in the army .'
[EX A]: declared

[EX Q]: Given Relationship: 'be chairman of', Sentence: 'President Bush named his top economic advisor , Ben Bernanke to replace economic legend Alan Greenspan as the chairman of the Federal Reserve .'
[EX A]: chairman

[EX Q]: Given Relationship: 'file to', Sentence: 'It is a powerful software for ripping audio CD tracks to files of audio formats MP3 , WAV , WMA , and OGG Vorbis on-the-fly .61 .'
[EX A]:
files