During the sunrise periods, many new domain names were registered.

The company's accounting periods are from January to December.

There are zero periods in this sentence.

I have been experiencing irregular menstrual periods lately.

The sidereal periods of the planets vary greatly.

Employees are required to give two months' notice periods before resigning.

During question periods, the members of parliament can ask the government ministers about various issues.

During the school day, students have several free periods to study or relax.

Elephants have long gestation periods.

During their honeymoon periods, the newlyweds traveled to different countries.