Sentence:  A special grandstand , protected by awnings from the midsummer sun of Illinois , should be erected for occupancy by honored guests , who should include the ambassadors of all those new African nations as yet not quite convinced that the United States <WSD>is</WSD> thoroughly civilized . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)