问题 单项选择题

根面龋最易找到的细菌是

A.乳杆菌
B.螺旋体
C.放线菌
D.范永菌
E.变形链球菌

答案

参考答案:C

解析: 放线菌是人口腔正常菌丛中最常见的革兰阳性丝状菌,粘性放线菌促进变形链球菌定殖于根面,对根面菌斑形成根面龋的发生可能有重要的协同作用;乳杆菌使口腔的正常菌群,它可能不是龋病发生的初始致病菌,但参与龋病的发展,可能是导致牙本质龋、根面龋发展的致龋菌之一;变形链球菌有强的致龋性,它不仅是冠部龋病的主要致病龋,也是根部的主要致病龋。综上所述,答案为C。

完形填空
完形填空。
     We convince ourselves that life will be better after we get married, have a baby, then another. Then
we're dissatisfied that the kids aren't old enough and we'll be more  1  when they are. After that, we're
frustrated that we have  2  teenagers to deal with. We'll certainly be happy when we are out of that  3  .
   We tell ourselves that our life will be  4   when we get a nice car, are able to go on a nice vacation
and when we retire.
   But the 5  is: there is no better time to be happy than right now. Your life will always be filled with
challenges. It's best to  6   this and decide to be happy anyway.
   One my  7  quotes (语录) comes from Alfred D. Souza, who said, "For a long time it had seemed to
me life was about to begin---real life. But there was always some  8 in the way." This viewpoint has
helped me to see that there is no  9  to happiness. Happiness is the way itself. So, 10 every moment that
you have now and share it with your loved ones… and 11  that time waits for no one.
   So,   12   waiting until you finish school, until you go to university, until you start work, until you find a
boy or girl friend, until you get married, until you get a new car or home, until you have kids, until your
kids leave the house, until you get   13  , until you get remarried, until you retire, until spring, until
summer,…
( )1. A. available
( )2. A. troublesome
( )3. A. problem  
( )4. A. normal  
( )5. A. truth    
( )6. A. recall    
( )7. A. famous    
( )8. A. barrier    
( )9. A. time       
( )10. A. treasure
( )11. A. think    
( )12. A. keep    
( )13. A. satisfied
( )14. A. more    
( )15. A. vacation  
B. content
B. foolish
B. routine  
B. casual      
B. problem    
B. confirm  
B. direct    
B. attraction  
B. way        
B. spend    
B. forget    
B. stop    
B. stressed  
B. longer    
B. destination
C. confident
C. naive      
C. stage    
C. simple    
C. doubt     
C. admit    
C. valuable  
C. surprise      
C. limit      
C. celebrate    
C. remember  
C. practise  
C. divorced  
C. worse      
C. achievement
D. generous      
D. ridiculous    
D. area          
D. perfect        
D. answer        
D. trust          
D. favorite      
D. harm          
D. right          
D. develop        
D. confirm        
D. tolerate      
D. deserted      
D. better        
D. settlement    
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