In what three ways did the Chinese develop the perpetual calendar wan-nien-li? They observed the sun's longitude and the moon's phases. They used measurements from a sundial and a water clock. They de

In what three ways did the Chinese develop the perpetual calendar wan-nien-li?

They observed the sun's longitude and the moon's phases.

They used measurements from a sundial and a water clock.

They determined the dates of the two solstices in a year.

They mapped the constellations in the night sky.

They surveyed citizens about how many days there should be in a year.