TASK DEFINITION: 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.
PROBLEM: 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 .'

SOLUTION: President

PROBLEM: Given Relationship: 'invade', Sentence: 'Poland hopes Russia will invade Ukraine and give L\ 'viv to Poland for their support of invasion , as it has happened a few times in the past .'

SOLUTION: invade

PROBLEM: Given Relationship: 'be officer of', Sentence: 'Captain George Vancouver RN was an officer of the Royal Navy , best known for his exploration of North America , including the ...'

SOLUTION:
officer