在系统软件中，操作系统是最核心的系统软件，它是()
C
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Finally,thethiefhandedeverything____hehadstolentothepolice.
Thethief’s( )ofguiltclosedthecase.
Shonasaysthatinherquestionnaireheraimwas____.
The( )ofyellowandblueformgreen.
Doyouknowthereason____hewaslate?
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