Can I add existing RebusFarm users as subusers?
能否将现有 RebusFarm 用户添加为子用户？
No, subusers must be using an e-mail address which is not yet registered with any RebusFarm account.
不能，子用户使用的必须是尚未通过任何 RebusFarm 帐户注册的电子邮件地址。