From the given sentence, extract the phrase (often noun or verb) that carries the given relationship. The generated phrase should be present in the sentence.

Given Relationship: 'open on', Sentence: 'Registration is now open for the forthcoming test administrations on January 21 and February 10 , 2007 .'
open

Given Relationship: 'be cover by', Sentence: 'Hospice is covered under Medicare Part A .'
covered

Given Relationship: 'be know as', Sentence: 'The term Search Engine Optimization also known as SEO refers to optimizing the web pages as per the algorithms of the search engine used to rank web pages .'
known