[填空题]电能质量的基本指标是_____和_____，我国采用的工业频率是______HZ。

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• ●    Whether we will go or not __________ the weather.
• ●    Which ________ do you prefer, coffee or orange juice?
• ●    All tudent are eager to know ______________they wilt pa the exam or not
• ●    Table______ of tone or wood.
• ●    Do you feel like ________ to a film or would you rather ________ at home.
• ●    Without water, _________ no plant or animal.
• ●    I am wondering if they are ____ or____.
• ●    Will you be eating here or i thi to go? —Oh,____________,pleae.
• ●    决定供电质量的主要指标有_______、_______、_______、_______。
• ●    电能质量的基本指标是_____和_____，我国采用的工业频率是______HZ。
• ●    工厂供电的基本要求是_______，_______，_______，_______。
• ●    我国研制的平顶型可缩性金属支架基本结构有 ______ 、 ______ 和 ______ 三种。