The ancient Chinese divided a year into 24 equal __________ according to the positions of the sun on the ecliptic. Names were given with special __________ for these segments; such as vernal equinox (occurs on March 20 or 21) and pure brightness (occurs on April 4, 5, or 6); and hence they are called the 24 Solar Terms. __________ from the Reaches of the Yellow River, the 24 Solar Terms are basically a calendar to govern agricultural arrangements which takes into __________ the changes in climate and practical agricultural needs. The 24 Solar Terms are considered a great and __________ creation of the ancient Chinese.