One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft bodied and simply did not fossilize.

在这重要的一亿年的周期内缺乏化石（记录），关于这一点，有一种解释是早期的动物是软体动物，所以它们无法形成化石。

youdao

Closure of the hospitals was phased over a three-year period.

这些医院的关闭是在三年期间逐步进行的。

《牛津词典》

One interpretation regarding the absence of fossils during this important 100-million-year period is that early animals were soft-bodied and simply did not fossilize.

关于在这一亿年的重要时期中没有化石，有一种解释是，早期的动物是软体动物，根本不会变成化石。

youdao

In fact, the publication Science Watch listed her as the forty-ninth most-cited researcher in the world during that twenty-year period.

VOA: special.2010.05.18

In our first Yeats lecture, I was talking about Yeats's early development and stylistic transformation over the course of, roughly,a twenty-, twenty-five year period.

在我们讲叶芝的第一节课，我谈到叶芝的早期发展,以及他创作风格的转变，在大约20到25年的时间里。

耶鲁公开课 - 现代诗歌课程节选

Stocks have paid 4% more a year over this incredibly long time period than short-term bonds.

股票在相当长的一段时间里,每年都比短期债券投资收益率,高出4个百分点。

耶鲁公开课 - 金融市场课程节选