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{{u}} (31) {{/u}}thEy wErE likE nEwBorn ChilDrEn, unABlE to usE this{{u}} (32) {{/u}}tool. yEt onCE lAnguAgE DEvElopED, thE possiBilitiEs For humAn kinDs’ FuturE{{u}} (33) {{/u}}AnD CulturE growth inCrEAsED、 mAny linguists BEliEvE thAt Evolution is{{u}} (34) {{/u}}For our ABility to proDuCE AnD usE lAnguAgE. thEy{{u}} (35) {{/u}}thAt our highly EvolvED BrAin proviDEs us{{u}} (36) {{/u}}innAtE lAnguAgE ABility not FounD in lowEr{{u}} (37) {{/u}}. proponEnts oF this innAtEnEss thEory sAy thAt our{{u}} (38) {{/u}}For lAnguAgE is inBorn, But thAt lAnguAgE itsElF DEvElops grADuAlly, {{u}} (39) {{/u}}A FunCtion oF thE growth oF thE BrAin During ChilDhooD、thErEForE thErE ArE CritiCAl{{u}} (40) {{/u}}timEs For lAnguAgE DEvElopmEnt. CurrEnt{{u}} (41) {{/u}}oF innAtEnEss thEory ArE mixED, howEvEr, EviDEnCE supporting thE ExistEnCE oF somE innAtE ABilitiEs is unDEniABlE. {{u}} (42) {{/u}}morE AnD morE sChools ArE DisCovEring thAt ForEign lAnguAgEs ArE BEst tAught in{{u}} (43) {{/u}}grADEs. young ChilDrEn oFtEn CAn lEArn sEvErAl lAnguAgEs By BEing{{u}} (44) {{/u}}to thEm, whilE ADults hAvE A muCh hArDEr timE lEArning AnothEr lAnguAgE onCE thE{{u}} (45) {{/u}}oF thEir First lAnguAgE hAvE BEEn Firmly FixED、 {{u}} (46) {{/u}}somE AspECts oF lAnguAgE ArE unDEniABly innAtE, lAnguAgE DoEs not DEvElop AutomAtiCAlly in A vACuum.ChilDrEn who hAvE BEEn{{u}} (47) {{/u}}From othEr humAn BEings DE not possEss lAnguAgE. this DEmonstrAtEs thAt{{u}} (48) {{/u}}with othEr humAn BEings unnECEssAry For propEr lAnguAgE DEvElopmEnts. somE linguists BEliEvE thAt this is EvEn morE BAsiC to humAn lAnguAgE{{u}} (49) {{/u}}thAn Any innAtE CApACitiEs. thEsE thEoriEs viEw lAnguAgE As imitAtivE, lEArnED BEhAvior. {{u}} (50) {{/u}}, 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.

A．isolAtED
B．protECtED
C．DiFFErEnt
D．DistinguishED