The Sumerians estimated the length of the Moon's cycle to be over 29 days, and so they allotted 30 days to each month.
(they; allotted; 30 days; to each month) (The Sumerians; estimated; the length of the Moon's cycle to be over 29 days) Context(The Sumerians estimated,List([0, 23))):(the length of the Moon's cycle; to be; over 29 days)
The Sumerians estimated,List([0, 23))
they The Sumerians the length of the Moon's cycle
allotted estimated to be
30 days to each month
the length of the Moon's cycle to be over 29 days
over 29 days