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.

Q: Given Relationship: 'be president of', Sentence: 'On Tuesday , November 4 , 2008 at about 8pm Pacfic Time , the major news networks officially called the election for the President of the United States of America for Democratic Candidate Barack Obama .'

A: President
****
Q: Given Relationship: 'be date', Sentence: 'Witherspoon , who is dating Jake Gyllenhaal , tells Parade magazine , " There are things in my life that are hard to reconcile , like divorce .'

A: dating
****
Q: Given Relationship: 'be head of', Sentence: 'The head of the International Atomic Energy Agency , Mohamed ElBaradei , has told US diplomats that developing new weapons could encourage other countries to violate the nuclear non-proliferation treaty .'

A:
head
****