Sentence:  Such an instrument is expected to <WSD>be</WSD> especially useful if it could be used to measure the elasticity of heavy pastes such as printing inks , paints , adhesives , molten plastics , and bread dough , for the elasticity is related to those various properties termed `` length '' , `` shortness '' , `` spinnability '' , etc. , which are usually judged by subjective methods at present . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)