以下关于路由器物理端口的描述中，正确的是(21)。

(75)

(74)

(72)

(73)

某网络集成公司对某种网络设备的年需要量为5000件，单价为2000元，年储存成本为单价的15%，每次订货的订购成本为300元，平均交货时间为10天。一年按365天计算，则该网络设备的全年库存总成本为(70)。

A project management technique that is currently in widespread use is the(71). The purpose of this technique is to detail, in hierarchical fashion, all of the activities that are required to meet project objectives. There are some special activities called(72), which are events that signify the accomplishment or completion of major deliverables during the project. Most system development methodologies also provide(73), whose purpose is to contain the various pieces of relevant information - feasibility assessments, schedules, needs analysis, and so forth - in a single place so that they can be presented to project clients and other related parties. Several types of important network diagrams are used in project management.(74)was developed to make clear the interdependence between project tasks before those tasks are scheduled．(75)offers the advantage of clearly showing overlapping tasks.

某学院10名研究生(B1～B10)选修6门课程(A～F)的情况如表4-3(用√表示选修)所示。

 现需要安排这6门课程的考试，要求如下。  ①每天上、下午各安排一门课程考试，计划连续3天考完。  ②每个研究生每天只能参加一门课程考试，在这3天内考完全部选修课程。  ③在遵循上述两条要求的基础上，各课程的考试时间应尽量按字母升序做先后顺序安排(字母升序意味着课程难度逐步增加)。  为此，各门课程考试的安排顺序应是(68)。

当评估和选择最佳系统设计方案时，甲认为可以采用点值评估方法，即根据每一个价值因素的重要性，综合打分来选择最佳的方案。乙根据甲的提议，对表4-4所示的系统A和B进行评估，那么乙认为(69)。

信源以3:2的比例分别发出信号“1”和“0”。由于信道受到干扰，当发出“1”时，接收到“1”的概率为0.8，当发出“0”时，接收到“0”的概率为0.9。那么信宿接收到“0”时未产生误码的概率为(67)。

GB/T19000-2000(idt IS09000-2000)表示(65)国际标准。