Modern methods for tracking polar bear populations have been employed only since the mid-1980s, and are expensive to perform consistently over a large area.

跟踪北极能种群的现代方法仅在20世纪80年代中期才被采用，而且，要在大范围内连续采用这种方法，其代价非常高昂。

youdao

Now, you can can build indexes over XML data, and perform shredding using a call to a stored procedure.

现在，可以在 XML 数据上建立索引，并通过调用存储过程执行分解。

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One color will likely perform better over the others, but we're not far from where we started.

一种颜色可能表现比其他颜色要好，但是我们的改变还不大。

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The Modern Jazz Quartet continued to perform all over the world for sold-out crowds until the late nineteen seventies.

VOA: special.2009.03.01

To perform the compressions, place one hand over the other and press firmly on the center of the victim's chest.

VOA: special.2009.08.11

There are over one hundred Shakespeare festivals and many permanent theaters that perform his works.

VOA: special.2010.01.13

If history is any guide, a new marriage of elephants would neither disappoint nor over-perform.

ECONOMIST: Merkel clinches it, but the price is high | The

"Commodities, over time, perform much better in a rising interest-rate environment, " Mr. Johnson says.

WSJ: A Buy Signal for Commodities

The result is a rich database about how certain vehicles perform over time.

FORBES: How To Predict What Will Go Wrong With Your Car Down The Road