The Technical Contact is the person responsible for maintaining the DNS nameservers associated with the domain name. This enables that contact to make updates if necessary if, for example, the name of the DNS nameserver changes.
域名技术负责人负责维护DNS，包括DNS的修改等。

The Billing Contact is the primary point of contact responsible for paying for the domain name's license renewals.
域名帐单联系人：负责域名费用的支付。

In the case of a company, the company itself would normally be the Registrant. An officer or possibly a trusted employee of the company would be the Administrative Contact. The Technical Contact would normally be the ISP or webhosting provider (maybe us if you use these services).

所以，对一个公司来说，公司做为域名注册持有人，公司负责人或信得过的职员做为域名管理负责人，而域名技术负责人一般是ISP提供商或空间提供商。