Century: the unit for calculating years, with one hundred years as a century.

The big month (3 1 day) includes:1\ 3 \ 5 \ 7 \ 8 \10 \ 65438+February.

Big month: refers to the month with 3 1 day in the solar calendar (Gregorian calendar), and the seven months of Gregorian calendar, including 1 month, March, May, July, August,1month and1February, are big months with 3 1 month.

Abortion (30 days) includes: April \ June \ September \165438+1October.

Abortion: refers to a month with 30 days in the solar calendar or 29 days in the lunar calendar.

February 28th in a normal year and February 29th in a leap year.

Average year: A year in which there is no leap day in the solar or lunar calendar, or a year in which there is no leap month in the solar or lunar calendar.

There are 365 days in a normal year and 366 days in a leap year.

Leap year: A year with a leap day in the solar or lunar calendar or a leap month in the lunar calendar.

1 day =24 hours 1 hour =60 minutes.

Day: A unit of time based on the earth's rotation period, equal to 86,400 seconds south latitude.

Minute: the auxiliary unit of time.

1 minute =60 seconds 1 hour =3600 seconds.

Seconds: the basic unit of time.