Lyingundertheskull,thehumanbraincontainsanaverageoftenbillionnervecellscalled______.

Thisisanimportantproblem_______toofewsocialscientistshaveresearched.

Accordingtothe"principles-and-parameters"theory,"principles"refertohighlyabstractpropertiesofgrammarwhichareappliedtolanguageingeneralandwhichgeneratephrasesandatthesametimerestrainthepowerofMovea,while"parameters"allowgeneralprinciplestooperateincertainrestrictedways,accordingtowhichparticulargrammarsofnaturallanguagesvary.

Fromthesociolinguisticperspective,aspeechvarietyisnomorethanadialectalvarietyofalanguage.

ThedivisionofEnglishintoOldEnglish,MiddleEnglish,andModernEnglishisnonconventionalandnotarbitrary.