The aim is to reverse the decline in the number of tree species or at least to preserve the "genetic material" of all of them.

其目的是扭转树种数量下降的趋势，或至少保存所有树种的“遗传物质”。

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Changes in the visa process caused a dramatic decline in the number of foreign students seeking admission to U.S. universities.

签证程序的变化导致申请美国大学的外国学生数量急剧下降。

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With this new use for salicylates, we can expect a continued steady decline in the number of headaches suffered by the average citizen of Mentia.

有了水杨酸盐的这种新用途，我们可以预期 Mentia 普通市民患头痛的数量会持续稳步下降。

youdao

We ,over the last twenty-five years, seen an alarming decline in the number of beekeepers.

VOA: special.2011.05.24

Global Witness says trends in the number and average size of oil discoveries has been in decline since 1965.

VOA: standard.2009.10.20

Meanwhile,with global growth expected to top four percent in 2010 compared to a decline of .6 percent in 2009, industry leaders in the United States say they are optimistic that the total number of foreign visitors will start to grow.

VOA: standard.2010.05.04

The Tory AM also highlighted the decline in the number of pupils achieving top grades in Wales.

BBC: Conservatives' debate

There has been a decline in the number of stillbirths, with the steepest fall between 1979 and 1983.

BBC: Wintry nights spark summer births

Adding to the price tag is a steady decline in the number of domestic workers in the market.

FORBES: Brazil's 'Poor' Middle Class, And The Poor That No Longer Serve Them