Sentence:  As to relative frequencies of competing roots ( 7 - 1 vs. 4 - 4 , etc . ) , Thomas with his ' weighting ' seems to <WSD>be</WSD> the first to have considered the significance this might have . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)