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.

Sentence: 'The World Conference of Associations of Theological Institutions holds its fourth world congress from 30 May to 7 June in Thessaloniki , Greece .', Argument/Subject 1: 'conference', Argument/Subject 2: 'june'
be hold in

Sentence: 'Bill served his country in the U.S. Navy for three years before marrying in 1961 .', Argument/Subject 1: 'bill', Argument/Subject 2: 'us navy'
serve in

Sentence: 'The election of Illinois Senator Barack Obama as America 's 44th president is astounding , historical , implausible , improbable and completely without precedent in the history of the United States .', Argument/Subject 1: 'obama', Argument/Subject 2: 'america'

be president of