From childhood to old age, we all use language as a means of broadening our knowledge of ourselves and the world about us.When humans first __1__ , they were like newborn children, unable to use this __2__ tool.Yet once language developed, the possibilities for human kind‘s future __3__ and cultural growth increased.
     
     Many linguists believe that evolution is __4__ for our ability to produce and use language.They __5__ that our highly evolved brain provides us __6__ an innate language ability not found in lower __7__ . Proponents of this innateness theory say that our __8__ for language is inborn, but that language itself develops gradually, __9__ a function of the growth of the brain during childhood.Therefore there are critical __10__ times for language development.

Current __11__ of innateness theory are mixed, however, evidence supporting the existence of some innate abilities is undeniable. __12__ , more and more schools are discovering that foreign languages are best taught in __13__ grades.Young children often can learn several languages by being __14__ to them, while adults have a much harder time learning another language once the __15__ of their first language have become firmly fixed.

　　__16__some aspects of language are undeniably innate, language does not develop automatically in a vacuum.Children who have been __17__ from other human beings do not possess language.This demonstrates that __18__ with other human beings isnecessary for proper language development.Some linguists believe that this is even more basic to human language __19__ than any innate capacities.

These theorists view language as imitative, learned behavior. __20__ , children learn language from their parents by imitating them.Parents gradually shape their child's lang uage skills by positively reinforcing precise imitations and negatively reinforcing imprecise ones.
 
1.A.generated          B.evolved        
   C.born                  D.originated

2.A.valuable            B.appropriate  
   C.convenient         D.favorite

3.A.attainments        B.feasibility      
   C.entertainments   D.evolution

4.A.essential            B.available      
   C.reliable             D.responsible

5.A.confirm             B.inform           
   C.claim                 D.convince

6.A.for                    B.from             
   C.of                      D.with

7.A.organizations      B.organisms    
   C.humans               D.children

8.A.potential            B.performance
   C.preference         D.passion

9.A.as                      B.just    as          
   C.like                    D.unlike

10.A.ideological        B.biological      
    C.social                D.psychological

11.A.reviews              B.reference     
    C.reaction              D.recommendation

12.A.In a word          B.In a sense    
     C.Indeed              D.In other words

13.A.various              B.different       
     C.the higher          D.the   lower

14.A.revealed            B.exposed       
    C.engaged              D.involved

15.A.regulations         B.formations    
     C.rules                  D.constitutions

16.A.Although            B.Whether       
    C.Since                  D.When

17.A.distinguished      B.different       
    C.protected           D.isolated

18.A.exposition          B.comparison  
     C.contrast            D.interaction

19.A.acquisition          B.appreciation
    C.requirement         D.alternative

20.A.As a result          B.After all        
     C.In other words    D.Above all