命题“对于任意角θ,cos4θ-sin4θ=cos2θ”的证明:“cos4θ-s

题型:选择题

问题:

命题“对于任意角θ,cos4θ-sin4θ=cos2θ”的证明:“cos4θ-sin4θ=(cos2θ-sin2θ)(cos2θ+sin2θ)=cos2θ-sin2θ=cos2θ”过程应用了(  )
A.分析发
B.综合法
C.综合法、分析法结合使用
D.间接证法
考点:综合法与分析法
题型:选择题

在⊙O中,弦AB<CD,OE、OF分别是O到AB和CD的距离,则(  )

A.OE>OF

B.OE=OF

C.OE<OF

D.无法确定

题型:选择题

下列哪项检查阳性表示乙型肝炎患者传染性强()

A.HBsAg

B.抗-HBs

C.HBeAg

D.抗-HBe

E.抗-HBc

题型:选择题
完形填空。
     What will city life be like in the future? Some people think that life in the cities is going to be   1  . They   2   
that cities will become more and more crowded.   3   the number of people increases, there will be less space for
each person. This   4   will cause other problems-more crimes, dirtier streets, and worse problems with traffic
  50  we have now. How will people find enough drinking water, energy (such as gas and electricity), and
housing?   6   life will be hard, people who live in cities will worry more, and they may become sick.   7   these
reasons, some say that nobody will want to live in urban areas.
     How can we   8   such problems as overcrowding, crime, and traffic? In some cities, thousands of people
are already   9   in the streets because there is so little suitable housing-and because  10  are so high. The crime
rate isn't going down.  11 , it is,  12  so fast that many people are afraid to go out at night. Traffic jams are so
bad that cars don't move at all for several blocks. These  13  problems have been getting worse, not better, so
many people see no  14  for the future of the city.
     However, not all people believe in the horrible  15  for cities of the future. Instead, they feel that they can
solve present urban problems and  16  future ones.
     The disadvantages of any modem city are not unique (独特的) to that city.  17 , all the cities in the world
have to solve the problems of traffic jams, crime, housing, energy, drinking water and overcrowding. Yet many
cities have found answers to one or more of these difficulties. Some European cities, such as Stockholm,
Sweden, or London, England, have planned communities that  18  people with apartments, jobs, shopping centers,
green space, entertainment and transportation. Many U.S. cities are building their downtown areas. Urban  19  
can learn from one another. They can  20  solutions that have been successful in other parts of the world.
( )1. A. horrible       
( )2. A. ensure         
( )3. A. With           
( )4. A. room           
( )5. A. than           
( )6. A. While          
( )7. A. With           
( )8. A. deal           
( )9. A. begging        
( )10. A. fiats         
( )11. A. Instead       
( )12. A. raising       
( )13. A. rural         
( )14. A. reality       
( )15. A. predictions   
( )16. A. reform        
( )17. A. That's to say 
( )18. A. provide       
( )19. A. consumers     
( )20. A. identify      
B. amazing       
B. predict      
B. Though        
B. overcrowding     
B. which         
B. Once          
B. For            
B. manage       
B. starving        
B. rents      
B. Thus           
B. changing       
B. urban          
B. trend         
B. definitions   
B. remain        
B. For example   
B. satisfy       
B. systems         
B. try        
C. regular          
C. indicate         
C. As               
C. future           
C. what             
C. Therefore        
C. Because of       
C. cause            
C. robbing          
C. cars             
C. Yet              
C. dropping         
C. crime            
C. hope             
C. identification   
C. cure             
C. What's more      
C. offer           
C. planners         
C. cure           

D. virtual             
D. require          
D. Unless              
D. number           
D. as                
D. Because           
D. Thanks to         
D. solve             
D. sleeping          
D. crimes            
D. However           
D. increasing        
D. traffic           
D. prediction        
D. indication        
D. prevent           
D. On the other hand        
D. require           
D. physicians        
D. forecast          

题型:选择题

每一级轻型井点的降水深度,一般不超过()m。

题型:选择题

CSK—1A试块φ1.5横孔用来测量斜探头K()的探头。

A、>1.5

B、>2

C、>2.5

D、>3

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