單項選擇題（） is not a physical wall, but a lot of virtual data to protect the computer network.

A. Date wall   
B. Date channel   
C. Database   
D. Firewall


你可能感興趣的試題

1.單項選擇題（） is meant to provide facility for customer s need or inquiry and arrange it.

A. Service  
B. Business  
C. Customer service  
D. Making money

2.單項選擇題Saving or reducing expenditure in business is（）

A.Save money  
B.Increase cost  
C.Cost planning  
D.Cost control

3.單項選擇題Re-handling can save cost and improve service, Is it true or not? （）

A. Wrong
B. Not total true
C. True
D. Not clear here

4.單項選擇題Where is the rail service better than U.S? （）

A.Canada 
B.Europe 
C.Japan 
D.Nowhere

5.單項選擇題If you make different trade in different countries, you must take different transport modes? （）

A.Yes    
B.Not    
C.It must be based on cost    
D.Not mention in the paragraph