Sentence:  Ontario 's foliage <WSD>is</WSD> most vivid from about Sept. 23 to Oct. 10 , with both Muskoka ( 100 miles north of Toronto ) and Haliburton ( 125 miles northwest of Toronto ) holding color cavalcades starting Sept. 23 . 
Meaning of the word marked with <WSD> tags:  have the quality of being; (copula, used with an adjective or a predicate noun)