Originally, geological history was divided into four spans of time—primary, secondary, tertiary, and quaternary.

最初, 地质历史被分为四个时间跨度 - 初级, 二级, 三级和四级。

Go through primary, secondary, tertiary, quaternary.

- 经历小学、学、大学、四年级。

In a recent paper of his own he tried to calculate how many stable crystals incorporating four chemical elements (so-called quaternaries) might be potentially manufacturable.

在自己最近的一篇论文，图计算有多少含有四种化学素的稳定晶体(所谓的季盐化)以被制造出来。

In some books, too, you will find the tertiary and quaternary taken out and replaced by periods of different lengths called the Palaeogene and Neogene.

在有的书里，你还会发现不用第三纪和第四纪，而是用不同长度的系来取而代之，称做下第三系和上第三系。

In some books, too, you will find the tertiary and quaternary taken out and replaced by periods of different lengths, called the Paleogene and Neogene.

在一些书, 你会发现第三纪和第四纪被取出, 取而代之的是不同长度的时期, 称为古近纪和新近纪。

The fossil is estimated to date back to a time between the late Middle Pleistocene and the Late Pleistocene of the Quaternary period, between 200,000 and 10,000 years ago.

这具化石估计以追溯到第四纪晚更新世至晚更新世时期，大约在20万到1万年前。

Along with the mammoth and the dire wolf, the sabre-toothed tiger was a casualty of the Quaternary extinction, A die-off that happened between 50,000 and 10,000 years ago that seems to have affected big animals in particular.

与猛犸象和恐狼一样，剑齿虎也是第四纪灭绝的受害者。这次灭绝发生在大约5万到1万年前， 特别影响到了大型动。