This system user must first carry on the debarkation, then uses the system to carry on the communication again. 该系统用户首先要进行登陆，然后再使用系统进行信息交流。
It is impossible to design appropriate behaviors for a system without understanding the users of the system in specific detail. 未详细理解系统用户的具体细节，就不可能设计系统的合适行为。
