Sometimes you may forget what the date is on a certain day.

有时候，在一些特定的日子里，你可能会忘记那天是几月几号？

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On a certain day at a certain hour, we will pull into the station. Bands will be playing and flags waving.

在某一天的某一时刻，我们的火车将会到站，迎接我们的将是演奏的乐队和飘舞的旗帜。

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Now upon a certain day when his sons and daughters were eating and drinking wine in the house of their eldest brother.

有一天，他的儿子同他的女儿，正在长兄家里欢宴饮酒的时候。

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"Whereas the oil industry may find it business as usual to have a certain number of spills, it is really not acceptable, especially in this day and age.

VOA: special.2011.07.08

But wouldn't it be nice to just have a certain period of time every day when you didn't have to even have it be ? so much as a remote possibility?

但要是每天能有一段特定的时间,死亡对你来说,甚至连一个遥远的可能性都不是,那岂不是很好？

耶鲁公开课 - 死亡课程节选

"Our health and wellness committee provided us with pedometers and there was a contest to see how many people could log ten thousand or more steps each day over a certain period.

VOA: special.2011.02.28

Such performance-based exams have a big advantage over multiple choice: They go beyond whether students can regurgitate a set of facts on a certain day to assess their know-how.

FORBES: Instant feedback in the classroom

All of these facts together may make it seem more likely that kids are getting a fever on a certain day of the week even though it may just be a coincidence.

CNN: Why do kids always get fevers on Sunday nights?

In the swap, Enron agreed to pay the billing service for heating degree days above a certain amount, and get paid for every heating degree day below a certain amount.

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