问题 填空题

为了便于系统控制和描述进程的活动过程,在操作系统核心中为进程定义了一个专门的数据结构,称为______。

答案

参考答案:进程控制块或PCB

解析: 创建一个进程的主要任务是建立进程控制块PCB。具体操作过程是:先申请一空闲PCB区域,将有关信息填入PCB,置该进程为就绪状态,最后把它插入到就绪队列中。

完形填空
完形填空。
     Today the problem of environment has become more and more serious. Every day, every hour, the air,
forests, soil, oceans and fresh    1     are becoming dirtier and dirtier. There are two     2     for the problem: the excessive (过度) use of natural resources and pouring a lot of     3     waste in the course of production. 
     Yet, man    4     great progress in environmental protection. Scientists and inventors are trying to
develop    5      engines for automobiles. Governments of many countries have made    6     to protect the
natural resources. More and more people have realized the importance of environmental protection and are doing what they can to protect our surroundings.
     Still more ways     7     to solve the problem. People should be educated in       8      modern methods to protect the environment and learn to make clever use of recycling our natural resources. The government of all       9       should take ways to fight against pollution _    10   _ protecting the environment is not only
protecting our home but also the civilization (文明) of the humankind.
( ) 1. A. water      
( ) 2. A. ways      
( ) 3. A. pollution  
( ) 4. A. makes      
( ) 5. A. cleaner    
( ) 6. A. ways      
( ) 7. A. should take
( ) 8. A. using      
( ) 9. A. schools    
( ) 10. A. so        
B. air      
B. reasons  
B. polluted
B. made    
B. dirtier  
B. laws    
B. taking  
B. taking  
B. cities  
B. because  
C. food          
C. things        
C. polluting      
C.  has made      
C. Worse          
C. rules          
C. should be taken
C. having        
C. countries      
C. because of    
问答题