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.

[Q]: Sentence: 'XHTML provides the framework for future extensions of HTML and aims to replace HTML in the future .', Argument/Subject 1: 'html', Argument/Subject 2: 'xhtml'
[A]: be replace by

[Q]: Sentence: 'Copernicus went on to attend Cracow University where he studied optics and mathematics .', Argument/Subject 1: 'copernicus', Argument/Subject 2: 'cracow'
[A]: attend university of

[Q]: Sentence: 'On Feb 10 , Barack H. Obama , the Democratic Senator from Illinois stood on the steps of the old Illinois Capitol in Springfield and gave a 21 min landmark discourse that culminated in the much anticipated official declaration of his run for US president in 2008 .', Argument/Subject 1: 'obama', Argument/Subject 2: 'illinoi'
[A]:
be senator from