Which of these correctly identifies a difference between the way BPDUs are handled by 802.1w and 802.1D？ （） 802.1D bridges do not relay BPDUs.。 802.1w bridges do not relay BPDUs.。 802.1D bridges only relay BPDUs received from the root.。 802.1w bridges only relay BPDUs received from the root.。
重介质选煤的基本原理是（），即浸没在重介质中的颗粒受到的浮力等于颗粒所排开的同体积的介质重量。 牛顿定律。 阿基米德原理。 勾股定律。 二八定律。
You have done a partial migration from 802.1D STP to 802.1w STP. Which of the following is true？（） 802.1D and 802.1w interoperate only when the 802.1D STP domain supports rapid convergence.。 Ports leading to 802.1D devices will run in compatibility mode， while the rest of the ports will run in 802.1w mode.。 This is an invalid configuration and a partial migration cannot be done.。 The bridge timers will be set to match the 802.1D devices.。 A secondary root bridge will always be populated within the 802.1D domain.。 If the root bridge is selected within the 802.1D domain， the whole STP domain will run in 802.1D compatibility mode.。 In partially migrated 802.1w networks， it is recommended to keep the STP diameter below 4.。
列车经过隧道未开启照明灯，属于（）问题。 红线。 A1。 A2。 B。
体育课程实施的适应性
两台PC机之间采用全双工方式串行通信时，至少需要（）根信号线。
