相对年代和绝对年代。

Relative and absolute ages.

youdao

在整个地质年代中，浮游生物随地质时代的变化用于估计含己成为化石的浮游生物残体的岩石的相对年代很有用。

The changes in plankton over time are useful for estimation of relative ages of rocks that contain the fossilized remains of plankton.

youdao

到了19世纪90年代，自发的微笑相对容易捕捉，所以我们必须从别处寻找解释，为什么维多利亚时代的人仍然对微笑犹豫不决。

Spontaneous smiles were relatively easy to capture by the 1890s, so we must look elsewhere for an explanation of why Victorians still hesitated to smile.

youdao

So, Descartes lived in a fairly sophisticated time, and his time did have robots.

笛卡尔生活在一个,人类社会发展相对成熟的时代,在他生活的年代,已经出现了机器人

耶鲁公开课 - 心理学导论课程节选

Later on when times are more secure, there's trade for grain as well for everything else, but when you're settling a place in the first place, you can't rely on somebody bringing it to you.

在之后相对安定的年代,有了粮食及其他各种物品交易,但当你刚开始在某地定居时,并不能指望有人为你供给必需品

耶鲁公开课 - 古希腊历史简介课程节选