问题 完形填空
完形填空
     The night was dark, though sometimes the moving clouds allowed a star or two to be seen in the
sky. The poor men held on to any bit of wood they could find. They called to the Marie for   1  , but
she was far   2   the reach of the human voice. At one o'clock in the morning, the water was getting   3  ,
and a strong   4   had begun to blow. Suddenly   5   were seen in the distance; another ship! The shouts
of the swimmers were heard on board, and willing hands pulled them out of the water.
     The   6   of the ship that had so fortunately arrived on the scene in time to   7    their lives was the
Ellen. What had brought her to the exact spot through the   8   and the pathless sea? Her captain had
known   9   about the wreck (沉船) and had indeed tried to sail away from it. But let him speak for
himself.
     "I was forced by the wind," he said long afterwards, "to   10   my course (航道). Just as I did it, a
small   11   flew across the ship once or twice and then   12   at my face. I took no   13   of this until
exactly the same thing happened at a   14   time, which caused me to think it rather   15  , and while I
was thus 16   it, the same bird for the third time, made its appearance and flew   17   in the same way
as before. I was then   18 to change my course back to the original (原来的) one. I had not gone far
   19   I heard strange noises; and when I tried to   20   where they came from, I found I was in the
middle of people who had been shipwrecked. I immediately did my best to save them.
( )1. A. food    
( )2. A. between  
( )3. A. colder  
( )4. A. smoke  
( )5. A. people  
( )6. A. captain      
( )7. A. make    
( )8. A. light  
( )9. A. everything
( )10. A. continue
( )11. A. light  
( )12. A. flew  
( )13. A. notice
( )14. A. good  
( )15. A. unusual
( )16. A. searching
( )17. A. back  
( )18. A. decided
( )19. A. when  
( )20. A. make sure
B. help  
B. out  
B. deeper
B. wave  
B. houses
B. owner
B. lose  
B. wind  
B. anything
B. turn  
B. fly  
B. stopped
B. attention
B. second
B. funny
B. expecting
B. up    
B. advised
B. while
B. search for
C. rest  
C. beyond  
C. saltier
C. sand  
C. ships
C. name  
C. keep  
C. darkness
C. something
C. change
C. bird  
C. stayed
C. look  
C. third
C. common  
C. considering
C. about
C. persuaded
C. as    
C. listen to
D. stop        
D. in          
D. warmer      
D. wind        
D. lights      
D. person      
D. save        
D. water        
D. nothing      
D. sail        
D. plane        
D. looked      
D. interest    
D. long        
D. interesting  
D. studying    
D. down        
D. invited      
D. after        
D. look out    
答案

1-5:  BCADD    6-10:  CDCDC    11-15:  CAABA   16-20:  CCCAA

实验题

下面是关于果蝇对DDT抗药性的进化实验。

实验一:将一个果蝇群体(第-代)饲养到一定规模后,用涂有a浓度DDT的玻璃片处理,将成活下来的果蝇后代(第二代)继续饲养到一定规模后用2a浓度的DDT处理,将成活下来的果蝇的后代(第三代)用3a浓度的DDT处理……用同样的方法逐代将DDT浓度增加1a处理果蝇。到第15代,DDT浓度增加至15a仍有能抗15a浓度DDT的果蝇成活。因此,实验者认为,果蝇的变异是“定向的”,即是在环境条件(DDT)的“诱导”下产生的,并且认为,该实验证实了拉马克“用进废退学说”的正确性。另有学者发现了“实验一”设计的缺陷,怀疑实验一得出的结论的科学性。因而设计了实验二。

实验二:将若干对雌雄果蝇分别饲养成若干个家系(家系:一对果蝇子女),此为第一代,然后将每个家系分成两半,用a浓度分别处理每个家系的一半。然后在有果蝇成活的家系的另一果蝇中,再培养若干个家系(第二代)将每个家系分成两半,用2a浓度的DDT处理每个家系的一半。在有果蝇成活的家系的另一半中,再培养若干个家系(第三代),用3a浓度的DDT处理每个家系的一半……用同样的方法逐代将浓度增加1a处理果蝇。到第15代时,浓度增加至15a,也产生了能抗15a浓度DDT果蝇群体。然而,这些具有抗药性的果蝇的父母并没有接触过DDT。通过对实验二的分析后,你认为:

(1)DDT对果蝇变异所起的作用不是“诱导”而是__________,果蝇种群的进化是定向的,而果蝇个体的变异是__________的,果蝇抗药性的产生在环境变化(DDT处理)之(前、中、后)_________。

(2)通过对实验一和实验二的比较分析,你认为实验一得出不正确结论的原因是___________________。

单项选择题