Answer: Apple launched an insurance, commonly known as ac +, the purchase cost of 788 yuan, and can only be activated within 60 days to buy.

答：苹果推出的一项保险，俗称AC +，购买费用为788元，且只能在激活60天内购买。

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Ac Alternating current (ac) is electric current that alternates between a positive maximum value and a negative maximum value at a characteristic frequency, usually 50 or 60 cycles per second (Hertz).

交流交流是指电流在正负最大值之间以特定的频率变动，通常频率为50或60赫兹。

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Usually an off-the-shelf induction generator that produces 60-cycle AC electricity.

通常一起飞-现成的异步发电机产生6 0交流电的电力。

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Running an AC unit without a low-pressure cutoff switch when it's colder than about 60 degrees might damage it, says Troy Gregory, president of Standard Heating and Air Conditioning.

WSJ: Don't Wait to Service AC Units