问题
单项选择题
光纤收发器与用户设备连接后，网口灯都亮，但不通，可能的原因是速率不匹配，（）。
A.双工不匹配
B.直连/交叉网线不对
C.光纤收发器坏
答案
参考答案：C
搜题请搜索小程序“爱下问搜题”
光纤收发器与用户设备连接后，网口灯都亮，但不通，可能的原因是速率不匹配，（）。
A.双工不匹配
B.直连/交叉网线不对
C.光纤收发器坏
参考答案：C
| When you first drift off into slumber, your eyes will roll about a bit, your temperature will drop slightly, your muscles will relax, and your breathing will become quite regular. Your brain waves slow down a bit, with the alpha rhythm predominating for the first few minutes. This is the first stage of sleep. For the next 30 minutes or so, you will drift down through Stage 2 and Stage 3. The lower your stage of sleep, the slower your brain waves will be. About 40-60 minutes after you lose consciousness, you will reach the last stage. Your brain waves will show the delta rhythm. You may think that you stay at this deep stage all the rest of the night, but that turns out not to be the case. About 80 minutes after you fall into slumber, your activity cycle will increase slightly. The delta rhythm will disappear, to be replaced by the activity pattern of brain waves. Your eyes will begin to dart around under your closed eyelids. This period of Rapid Eye Movements lasts for 8-15 minutes and is called REM sleep. During both light and deep sleep, the muscles in your body are relaxed but capable of movement. As you slip into REM sleep, a very odd thing occurs -- most of the voluntary muscles in your body become paralyzed. Although your brain shows very rapid bursts of neural activity during REM sleep, your body is incapable of moving. REM sleep is accompanied by extensive muscular inhibition. |
The best title for this passage would be______.
A．Brain Waves
B．Sleep Cycles
C．Daily Activities
D．Body Activities