[填空题]由操作系统向用户程序提供了__________，这些子程序能帮助用户程序实现多种系统功能。

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• ●    A campu emergency ______ occur at any time of the day or night, weekend, or holiday, with little or no warning.
• ●    By no mean ______ detroy or create energy.
• ●    Ak Mr. Brown, or any other peron ______.
• ●    Our ucce _______ whether everyone work hard or not.( )
• ●    Morning or afternoon. It make no _______ to me.
• ●    Whether we will go or not __________ the weather.
• ●    Which ________ do you prefer, coffee or orange juice?
• ●    We hould not eat or eat le______ food.
• ●    Table______ of tone or wood.
• ●    Without water, _________ no plant or animal.
• ●    I am wondering if they are ____ or____.
• ●    _________ in a peron’ peech or writing uually range on a continuum from caual or colloquial to formal or polite according to the type of communicative ituation.