Sentence:  It <WSD>is</WSD> interesting to note how many of the plants on Massachusetts ' Route 128 draw most of their income either from the government in non-competitive cost-plus arrangements , or from the exploitation of patents which grant at least a partial monopoly . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)