Sentence:  It follows , then , provided the possibilities have been exhausted , that the only real alternative is the general viewpoint of the `` left '' , which has been represented on the Continent by Fritz Buri and , to some extent at least , is found in much that <WSD>is</WSD> significant in American and English theology . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)