All historical rates are stored by period and actuality, which means that you can go back to an old period and locate the exact values that were used during the currency conversion.

所有历史汇率都按期间和现状存储，这意味着您可以追溯到一个较早的期间并定位货币转换过程中使用的确切值。

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This is a painting earlier in the same period, from the hands of the old Brezhel.

这是同时期稍早时候的一幅画，出自老布勒哲尔之手。

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Six-week-old babies generally breastfeed seven to nine times in a twenty-four-hour period.

VOA: special.2010.08.04

and many of the anonymous poets from the old English period that I studied in my graduate school days.

还有许多我在大学里学过的古英语时期的匿名诗人。

我的专业 - SpeakingMax英语口语达人

The major highlights here are not only the exuberant floral designs that abound on the mosaic floor of the Church of the Virgin (itself built over a Roman temple), but the multiple layers of Madaba's history -- inhabited in some way since the Old Testament Exodus period -- which this tiny section of town reveals.

BBC: Travelling the slow route to Petra

There aren't many Western central banks with a worse forecasting record during this period than the Old Lady of Threadneedle Street.

BBC: Inflation: Balancing the risks

But rather than being a period in which old animosities and suspicions were overcome, the past 18 months have further strained the Iraqi society.

NPR: Petraeus, Crocker Brief Congress on 'Surge'