问题 问答题 简答题

塑件上带有的螺纹,可用哪些方法获得?每种方法的优缺点如何?

答案

参考答案:塑件上带有的螺纹既可以直接用模具成型,也可以在成型后用机械加工获得,对于需要经常装拆和受力较大的螺纹,应采用金属螺纹嵌件。直接用模具成型的螺纹,模具结构相对复杂些,但成型后不需在即加工;成型后用机械加工获得的塑件螺纹,模具结构简单,但增加了成型后的工序;塑件上采用金属螺纹嵌件,螺纹可经常拆卸,且可承受较大的力,但模具结构较复杂,模具不易实现自动化。

完形填空
完形填空。

     I can honestly say it was the best of times and the worst of times. I was joyfully expecting my first
child at the same time that my mother was   1   her battle with a brain tumor (瘤). For ten years, my
fiercely independent and   2   mother had fought, but none of the treatments had been successful.   3  ,
she never lost her ability to smile. But now, finally, she became totally   4   -unable to speak, walk, eat or
dress on her own.
     As she grew closer and closer to death, my   5   grew closer and closer to life inside me. My biggest
   6   was that their lives would never connect. I was sad not only at the   7   loss of my mother, but that
she and my baby would never know each other. Her doctor did not   8  any hope; they told us her time
was up.
      We brought Mother   9   to her own bed in her own house. As  10  as I could, I sat beside her and
talked to her about the baby moving inside me.
     On February 3, 989, at about the same time my labor (分娩)  11 , Mother opened her eyes. When
they told me this at the   12  , I called her home, "Mom, listen. The baby is coming! You're going to have
a new grandchild!"
     "Yes! Yes! I know!"
      Four beautiful words! The first  13  words she'd spoken in months! When I  14  again an hour later,
the nurse at her house told the   15  message: Mom sat up, smiling, with her oxygen tubes removed.
     When I brought Jacob home. Mom was sitting in her chair and  16   to welcome him. Tears of joy
blocked my vision as I  17  my son in her arms and she clucked (发出咯咯声) at him. They  18  .
     Then she quietly clipped hack into a coma (昏迷) and  19  peacefully. Memories of my son's birth
 will always be  20  for me, but it was then that I learned love has the power to overcome any worries
and any sorrow. And love can last forever. 

( )1. A.attending   
( )2. A.courageous  
( )3. A.So          
( )4. A.tired       
( )5. A.sorrow      
( )6. A.problem     
( )7. A.coming      
( )8. A.admit       
( )9. A.up          
( )10. A.soon       
( )11. A.started    
( )12. A.office     
( )13. A, common    
( )14. A.got up     
( )15. A.impossible 
( )16. A.likely     
( )17. A. hugged    
( )18. A.joined     
( )19. A.passed away
( )20. A.proud      
B. losing        
B. interesting      
B. Again            
B. blind          
B. love           
B. dream         
B. disappearing   
B. hold           
B. away            
B. fast            
B. failed          
B. hospital        
B. caring          
B. woke up         
B. possible         
B. ready            
B. threw            
B. knew            
B. turned over      
B. frightening    

C. defending     
C. funny         
C. Instead       
C.  disabled     
C. baby          
C. surprise      
C. falling       
C. drop          
C. about         
C. early         
C. ended         
C. house         
C. clear         
C. called up     
C. necessary     
C. free          
C. took          
C. nodded        
C. settled down  
C. bittersweet   

D. defeating              
D. lucky                    
D. Still                    
D. depressed              
 D. body                     
D. fear                   
D. unexpecting            
D. permit                 
D. home                     
D. often                   
D. continued              
D. station                  
D. correct                  
D. looked up                
D. terrible                 
D. nervous                
D. laid                   
D. cried                    
D. gave out                 
D. exciting               
名词解释