(74)systems　perform　basic　tasks,　such　as　recognizing　input　from　the　keyboard,　sending　output　to　the　display　screen,　keeping　trac

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问题 (74)systems　perform　basic　tasks,　such　as　recognizing　input　from　the　keyboard,　sending　output　to　the　display　screen,　keeping　track　of　files　and(75)on　the　disk,　and　controlling　peripheral　devices　such　as　disk　drives　and　printers.

选项 A、contents
B、directories
C、directions
D、direct