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.
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Question: Sentence: 'London is both the capital of England and the United Kingdom and it serves as the headquarters for the Royal Family .', Argument/Subject 1: 'london', Argument/Subject 2: 'england'

Answer: be capital of

Question: Sentence: 'Nazi Germany 's attack on the Soviet Union in June 1941 extended the zone of killing operations even farther east .', Argument/Subject 1: 'germany', Argument/Subject 2: 'soviet union'

Answer: attack

Question: Sentence: 'Before flight testing began , it was extensively used for investigation of flying characteristics and studies of control-system response , and it has been linked to Air Traffic Control at Orly airport , Paris , to enable ATC authorities to study techniques of integrating supersonic airliners into the existing operational patterns .', Argument/Subject 1: 'orly', Argument/Subject 2: 'pari'

Answer:
be airport of