It was the first day of the 10th moon.

It was the first day of the 10th moon.
It was the first day of the 10th moon.

It was the first day of the 10th moon.
这是十月份的第一天
the 1st moon 代表正月
the 10th moon 代表十月.

这是农历十月的第一天。
the first moon 正月