Which three of these statements about PPPoE are true？（） PPPoE can provide a host with access to a destination over Ethernet. You can have only one PPPoE session per PVC。 You must install PPPoE client software on all hosts that connect to the Ethernet segment. This means that the access provider must maintain a CPE。 You cannot use PPPoE with Cisco Service Selection Gateway。 PPPoE implementation is susceptible to broadcast storms and possible denial-of-service attacks。 Per-session accounting is possible， which allows the service provider to charge the subscriber based on session time for various services offered. The service provider can also require a minimum access charge。
医务人员在医院外，发现患者而加以治疗，这在法律上属于（） 多管闲事。 见义勇为。 强制诊疗。 非法行医。 无因管理。
刚性好变形小的电器绝缘件，应使用（） ABS。 酚醛塑料。 聚丙烯。 聚碳酸酯。
简述双闭环直流调速系统中电流调节器的作用。
非稳态扩散用的是下面哪种模型（） A高斯烟羽模型。 B高斯烟团模型。 C高斯烟团叠加模型。 D高斯叠加模型。
What level of logging is enabled on a Router where the following logs are seen？（）
