instruction:
Given two noun phrases (arguments) and relationship between them, form a sentence that expresses theses arguments with the given relationship.
question:
Relationship: 'be head of', Argument/Subject 1: 'president', Argument/Subject 2: 'executive'
answer:
The service has been dubbed Derivatives Collateral Net and automatically aggregates and nets the overall collateral obligations of its participants , explains Art Certosimo , executive vice president and head of Broker-Dealer Services at the bank .


question:
Relationship: 'be bear in', Argument/Subject 1: 'haye', Argument/Subject 2: 'covington'
answer:
Hayes was born in Covington , Tennessee , the second-born child of Isaac Sr . and Eula Hayes .


question:
Relationship: 'say in', Argument/Subject 1: 'obama', Argument/Subject 2: 'chicago'
answer:

Obama said at a news conference yesterday in Chicago .