Given a sentence and two mentions from the text (arguments), indicate a phrase (a verb or noun phrase) that describes the relationship between the provided arguments.

Ex Input:
Sentence: 'The largest member of OPEC , Saudi Arabia , controls one-fifth of the world 's crude reserves and constitutes more than 10 percent of world daily production of crude oil , making it one of the most critical suppliers influencing this market .', Argument/Subject 1: 'saudus arabium', Argument/Subject 2: 'opec'

Ex Output:
be member of

Ex Input:
Sentence: 'I was editor of Surfer magazine , and Richard Nixon was president of the United States .', Argument/Subject 1: 'nixon', Argument/Subject 2: 'unite state'

Ex Output:
be president of

Ex Input:
Sentence: 'Speeches by the President of the Athens Olympic Games Organising Committee , Gianna Angelopoulos , and the President of the International Olympic Committee , Jacques Rogge , followed the introduction of new members of the Athletes Commission .', Argument/Subject 1: 'jacque rogge', Argument/Subject 2: 'international olympic committee'

Ex Output:
be president of