根据国际饭店管理经验，超额订房的百分数可在（）。
A、无所谓
B、5-15%
C、10-20%
D、15-25%
参考答案：B
In the process of communication requirement analysis,the project manager should consider the number of potential communication channels or paths as an indicator of the complexity of a project's communications.According to Metcalfe's Law,a project with 10 stakeholders has（）potential communication channels.
A.10
B.45
C.50
D.100
在（）上严禁通过工作电流，且严禁断线。
A.N线
B.PE线
C.火线
D.相线
