    Sentence 1: What astronomer worked for Kublai    Sentence 2: Among Kublai Khgp's top engineers and  scientists was the ‘ston Ol Showing, who was  tasked with many public works projects and helped the  Yuan seform the lunisolar calendar to provide an accuracy    of 3286 4AMbilays of the year, which was only 26 seconds  off the m  “    te         in Gregorian calendar's measurement.