The rings are changed once every three months by the patient.

病人可以每三个月更换一次硅胶环。

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We get a change of laundry every one or two months, once every three months in summer.

我们每一两个月换洗一次衣服，夏天是每三个月。

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One company floundered because it answered requests for quotations only once every three months.

一家公司陷入了窘境就是因为该公司每三个月才回复一次估价申请书。

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Mutual fund holders only get that kind of information once every three months.

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Once every three months, mere mortals get a glimpse at the portfolios billionaire investing legends when they are required to disclosed their end-of-quarter holdings.

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Cyndi, now a 44-year-old mother of two, has had sex with her husband only about once every three months -- at his request -- for the entirety of their marriage.

CNN: When a woman doesn't want sex