Whois, in simple terms, is a database used to query whether a domain has been registered and for obtaining detailed information about the registered domain (such as the domain owner, registrar, registration date, and expiration date). By querying the domain Whois server, you can find the contact information of the domain owner, as well as the registration and expiration times. You can use this tool to make such queries!
Explanation of the Implementation of Domain Expiration Deletion Rules:

International Domains:
(1) The domain resolution is suspended on the expiration day. If it is not renewed within 72 hours, the domain DNS is pointed to an ad page (parked). The domain is reserved for 30-45 days after expiration (different registrars have different policies)
(2) After the reservation period, the domain enters a redemption period (REDEMPTIONPERIOD, 30 days)
(3) After the redemption period, the domain enters a deletion period of about 5 days. After the deletion period, the domain is released and can be registered by anyone.

Explanation of Domain Status:

Status Descriptions for .cn Domains:

Statuses starting with 'client' are states that can be added by the client (registrar)
Statuses starting with 'server' are states added by the server side (CNNIC)
Statuses that do not start with 'client' or 'server' are managed by the server side