Instructions:Select all the correct answers.

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

1.They observed the sun's longitude and the moon's phases.
2.They used measurements from a sundial and a water clock.
3.They determined the dates of the two solstices in a year.
4.They mapped the constellations in the night sky.
5.They surveyed citizens about how many days there should be in a year.