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: 'win', Sentence: 'The Boston Red Sox Sports Odds of winning the 2009 World Series are currently fourth best in baseball , at +800 .'
[EX A]: in

[EX Q]: Given Relationship: 'be president of', Sentence: 'Barack Obama today becomes the first black president of the United States of America .'
[EX A]:
president