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 kinds 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 language 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.feasibilityC.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.formationsC.rules D.constitutions
16.A.Although B.Whether C.Since D.When
17.A.distinguished B.differentC.protected D.isolated
18.A.exposition B.comparison C.contrastD.interaction
19.A.acquisition B.appreciation C.requirementD.alternative
20.A.As a result B.After allC.In other words D.Above all