不同物种之间的寿命存在显著差异，但在同一物种内，这一参数是相对稳定的。

There are striking differences in life span between different species, but within one species the parameter is relatively constant.

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铱存在于陨石和火山物质中，但在火山物质中同时包含高浓度的镍和铬。

Iridium occurs in meteorites and volcanic material, but in the latter case it is accompanied by elevated levels of nickel and chromium.

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非洲大部分地区的狮子已经消失了，但在过去的几年里，科学家们猜想这种大型猫科动物仍然存在于苏丹和埃塞俄比亚的偏远地区。

Lions have disappeared from much of Africa, but for the past few years scientists have wondered if the big cats were hanging on in remote parts of Sudan and Ethiopia.

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It probably has some risk, but the way we approximate things in finance, we take the government as riskless.

它可能存在一定的风险，但在金融学上，我们忽略其风险，将政府债券看作无风险。

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But in the science fiction story where there's a duplicate,it says, if there's branching,the no branching rule comes in.

但在科幻作品里，复制的案例是存在的，分裂出现时，在无分支的规定下。

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It might not have any electrons in it, but it still exists, so you need to draw these into your molecular orbital diagram.

也许它里面没有电子，但它是存在的，所以你需要在分子轨道图里画出来。

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