问题 单项选择题

When the system upon which a transport entity is running fails and subsequently restarts, the (21) information of all active connections is lost. The affected connections become half-open, as the side that did not fail does not yet realize the problem.
The still active side of a half-open connections can close the connection using a (22) timer. This timer measures the time the transport machine will continue to await an (23) of a transmitted segment after the segment has been retransmitted the maximum number of times.0
When the timer (24) , the transport entity assumes that either the other transport entity or the intervening network has failed. As a result, the timer closes the connection, and signals an abnormal close to the TS user.
In the event that a transport entity fails and quickly restarts, half-open connections can be terminated more quickly by the use of the RST segment, the failed side returns an RST i to every segment i that it receives, when the RST i reaches the other side, it must be checked for validity based on the (25) number i, as the RST could be in response to an old segment, if the reset is valid, the transport entity performs an abnormal termination.

A. data B. state C. signalD. control

答案

参考答案:B

完形填空
Cloze.
    Good afternoon, and welcome to England. We hope that your visit here will be a   1   one. Today I would
like to   2   your attention to a few of our laws.
    The first one is about drinking. Now you may not buy alcohol drinks in this   3   if you are under 18 years
of age, and your friends may not buy it for you,   4  .
     Secondly, surroundings. Enjoy yourselves by all means, but please don't make a lot of noise, particularly
at night. We ask you to   5   other people who may wish to be   6  
     Thirdly, crossing the road. Be careful, traffic moves on the   7   side of the road in this country. Use
pedestrian crossings and do not take any chances when crossing the road.
     My next point is about litter (throwing away waste material in a public place). It is an offence (违法) to
drop litter in the street. When you have something to throw away, please put it in your   8   and take it home,
or put it in a litter bin.
     Finally, as regards smoking, it is   9   the law to buy cigarettes if you are under 16 years of age.
     I'd like to finish by saying that if you require any sort of help, you should  10  the local police station.
( )1. A. pleased  
( )2. A. get    
( )3. A. town    
( )4. A. either   
( )5. A. respect 
( )6. A. silent   
( )7. A. front   
( )8. A. clothes 
( )9. A. against  
( )10. A. arrange  
B. welcome 
B. pay    
B. country  
B. too    
B. remain       
B. private  
B. right   
B. pocket  
B. for     
B. attract  
C. pleasant  
C. draw    
C. city    
C. also    
C. remind   
C. quiet   
C. left    
C. box    
C. behind   
C. maintain    
D. surprising 
D. move       
D. village    
D. however                  
D. remark      
D. alone      
D. back       
D. office     
D. above      
D. contact    
单项选择题