Sentence:  With justified bitterness the author speaks of `` what seems to me to have <WSD>been</WSD> an inexcusable body of ignorance about the nature of the Russian Communist movement , about the history of its diplomacy , about what had happened in the purges , and about what had been going on in Poland and the Baltic States '' . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)