[单项选择]Why is it appropriate to use conditional label advertising when deploying MPLS?（）
A. to make CEF tables smaller
B. to enable label switching on the frame mode interface
C. to restrict MPLS availability to predefined time periods
D. to restrict label switching to a limited number of networks
E. to restrict end users from seeing the routers in the MPLS network

[单项选择]Why is it appropriate to use conditional label advertising when deploying MPLS? （）
A. to make CEF tables smaller
B. to enable label switching on the frame mode interface
C. to restrict MPLS availability to predefined time periods
D. to restrict label switching to a limited number of networks
E. to restrict end users from seeing the routers in the MPLS network

[单项选择]Why was the umbrella returned after the second advertisement appeared in the newspaper [A] Because they wanted to get ten pounds. [B] Because they didn't want to get into trouble. [C] Because they wanted to be known for it.

[单项选择]According to the passage, why do ants use different compounds as trail pheromones
A. ( To reduce their sensitivity to some chemicals
B. ( To attract different types of ants
C. ( To protect their trail from other species
D. ( To indicate how far away the food is

[多项选择]Why do large OSPF networks use a hierarchical design？（）
A. to confine network instability to single areas of the network
B. to reduce the complexity of router configuration
C. to speed up convergence
D. to lower costs by replacing router swith distribution layer switches
E. to decrease latency by increasing bandwidth
F. to reduce routing overhead

[多项选择]Why does the data communication industry use the layered OSI reference model (Choose two.)（）。
A. It divides the network communication process into smaller and simpler components, thus aiding component development, design, and troubleshooting.
B. It enables equipment from different vendors to use the same electronic components, thus saving research and development funds.
C. It supports theevolution of multiple competing standards, and thus provides business opportunities for equipment manufacturers.
D. It encourages industry standardization by defining what functions occur at each layer of the model.
E. It provides a means by which changes in functionality in one layer require changes in other layers.

[单项选择]Why does the author use the term "the dividend" even though he has acknowledged that in fact it does not exist
A. He is attempting to describe a transmittal circumstance.
B. He is articulating a metaphysical theory.
C. He is clarifying a situation.
D. He is devising an econometric formula.

[单项选择]Why does IS-IS use the SPF algorithm?（）
A. to determine the pseudonode ID
B. to determine the next hop to a given destination
C. to determine the complete path to a given destination
D. to determine the number of routers present in a given area

[单项选择]Why do people always try and use as few words as possible when they cable Because ______.
A. more words cost more money
B. they think it unnecessary to use "little words"
C. few words can make everything clear
D. they hate to use auxiliary verbs like "do, does, are,is," and so on

[单项选择]Why shouldn't we use a word that can be found in any dictionary as a password
A. Because it can be easily remembered by a computer hacker.
B. Because computer programs can crack it.
C. Because computer hackers are determined to crack it.
D. Because the lists are so huge that the words are not easy to remember.

[单项选择]“Why didn't you use that printer ” “Because it wasn't ________ to fit it.”
A. enough good
B. good as enough
C. as enough good
D. good enough

[单项选择]Why did the men who made maps have to use their imagination
A. Each man wanted to have a different map.
B. They did not like to draw the world as it really was.
C. No one knew what the world was really like.
D. They did not remember what they had seen.

[单项选择]Why shouldn't we use the garden, ______
A. weather permitting
B. weather permitted
C. weather permits
D. weather having been permitted

[单项选择]Why can't writers for GQ use the same methods as writers for newspapers
A. Articles in GQ are not allowed to consist mainly of interviews.
B. Writers for newspapers do not have so much space to fill.
C. They want to be considered better than writers for newspapers.
D. They have been told to avoid the conventions of newspaper writing.

[单项选择] Why would you use the following FLASHBACK TABLE command？（）  FLASHBACK TABLE emp TO TIMESTAMP （’11：45’，’hh12：mi’）； 
A. to undo the changes made to the EMP table since the specified time
B. to restore the EMP table that was wrongly dropped from the database
C. to view the transactions that have modified the EMP table since the specified time
D. to view the changes made to the EMP table for one or more rows since the specified time
E. to recover the EMP table to a point in time in the past by restoring the most recent backup