Sentence:  Then he noticed, as a prosaic business man will notice suddenly, that a <WSD>skyscraper</WSD> which he has passed daily for months is out of line with its neighbor, that the seat behind the new little girl was unoccupied and that she stood alone in the aisle during exercises. 
Meaning of the word marked with <WSD> tags:  A very tall building with a large number of floors.