搜题请搜索小程序“爱下问搜题”
问题 单项选择题

单纵模激光器主要能量集中在主模，所以它的光谱宽度是按主模的最大峰值功率跌落到（）时的最大带宽来定义的。

A.10dB

B.-10dB

C.-20dB

D.20Db

答案

参考答案：C

完形填空
完形填空
       The Great Wall of China has a history of over two thousand years. It runs from the east to the west
in North China. It is about 6,300 kilometers   1   . It is often   2   "Ten-thousand-Li Great Wall". It is one
of the “Seven Wonders” of the ancient world.
       The Great Wall is wide enough for ten men to walk   3  . Horses can also run along it, too. The Great Wall   4   stones and bricks（砖）. There are huge stones on   5   side and on the highest part. But now
some sections of it are worn out.
       There are tall watch-towers alone the Great Wall. Once upon   6   time, the soldiers kept watching the enemies（敌人） in the watch-towers day and night. They made   7   on the towers to  8    each other
when the enemies came.
       Nowadays we don’t use the Great Wall to keep away the enemies any more. It is a famous place of
interest to all the people in   9   . Every year  10    people come to visit it form all over the world.
( )1. A.wide        
( )2. A. calling    
( )3. A. side by side
( )4. A. was made of        
( )5. A. both        
( )6. A. an          
( )7. A. fire        
( )8. A. tell        
( )9. A. Asia        
( )10.A. thousand     		B .tall            
B. call            
B. one by one      
B. was made from          
B. all              
B. a                
B. a kite          
B. talk            
B. the world        
B. a few thousand   		C. long                
C. called              
C. one after another  
C. was made in        
C. each                
C. the                  
C. a face              
C. speak              
C. Europe              
C. thousands of                                   
查看答案
多项选择题

关于BGP邻居建连的必备条件，描述错误的有（）

A.手工配置BGP邻居

B.两台邻居路由器间成功建立一条TCP连接

C.BGP邻居间交换链路状态信息

D.BGP邻居间必须配置MD5认证
查看答案