问题 问答题 简答题

数控机床的机械结构应具有良好的特性,主要包括哪些?

答案

参考答案:

数控机床的机械结构应包括高的刚度和抗振性、好的热稳定性、好的低速平稳性、高的几何精度和传动精度。

单项选择题
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                                                             Volunteer victims
     A man who dined regularly in his favorite restaurant complained about the bread.It wasn't    1   he
said, that other restaurants served lots of    2  . But here he got only one piece.
     So the next time he came in, they    3   him four pieces. He still said it wasn't   4  . For his next visit they put a large basket of bread on the table. But still he   5  ,"The other restaurants give all the bread you can
  6  ". 
     They decided to be    7  for him the next day. They had    8   an enormous loaf of bread. It was six feet long and two feet wide. Four people carried the loaf to his    9  .They plopped (使掉下) it down in front
of him. It took up half the table and over both sides.The chef stood back to see    11   the customer would react.
     He looked over the loaf and    12  ,"So, we're back to one piece again, aren't we?" Like this man, we
volunteer to be    13  . We believe life is unfair and people are    14  . We think everyone should know just how    15   things are and we feel obliged to tell them.
     The problem is that life sometimes is unfair,   16   the greater truth is that people can decide whether
they are victims or    17  . Happy people have learned that they cannot always    18   their
circumstances, but they can often decide how they will    19  .What life means to us is determined not so
much by what life brings to us as by the    20   we bring to life; not so much by what happens to us as by
our reaction to what happens.You were born to be a victor! You were meant to be happy!
( )1. A.cheap    
( )2.A.bread      
( )3.A.sold      
( )4.A.plent y    
( )5.A.disagreed  
( )6.A.eat        
( )7. A.useful  
( )8.A. arranged  
( )9.A.home      
( )10.A.got      
( )11.A.how      
( )12.A.shouted  
( )13.A.suffers  
( )14.A.different
( )15.A.terrible  
( )16.A.and      
( )17.A.champions
( )18.A.adjust    
( )19.A.respond  
( )20.A.meaning  
B.expensive    
B.fruit        
B.served      
B.delicious    
B.disapproved  
B.produce      
B.ready        
B.organized    
B.office      
B.fell        
B.what        
B.whispered    
B.losers      
B.untrustworthy
B.nice        
B.but          
B.conquerors  
B.match        
B.ignore      
B.attitude    
C.fair        
C.soup        
C.bought      
C.suitable    
C.praised      
C.bake        
C.sorry        
C.prepared    
C.table        
C.swung        
C.when        
C.commented    
C.assistants  
C.cruel        
C.hard        
C.even        
C.fighters    
C.control      
C.evaluate    
C.approach    
D.possible    
D.pudding    
D.prepared    
D.enough      
D.complained  
D.consume    
D.anxious    
D.ordered    
D.counter    
D.hung        
D.why        
D.yelled      
D.victims    
D.impatient  
D.fantastic  
D.if          
D.victors    
D.direct      
D.cooperate  
D.manner