Furthermore, the designs were covered with "desert varnish", a glaze that develops on rock surfaces over thousands of years of exposure to the elements.

此外，这些设计还覆盖有“沙漠清漆”，一种在岩石表面经过数千年在这些元素暴露下而形成的釉料。

youdao

Phthalates have been around for about 50 years, and it is unknown whether people's exposure has increased.

其实邻苯二甲酸酯已经存在50多年了，只是无人知晓人们与它的接触在不断增加。

youdao

Thus far, such side effects seen in clinical trials have been minor, but it sometimes takes years of exposure to a drug before deadly infections show up, he says.

迄今为止，临床试验中这方面的负面影响很小，但有时多年的药物使用可能会让致命感染出现。

youdao

But she says the research does show the need to study whether or not there are long-lasting effects of repeated exposure over several years.

VOA: special.2011.03.02

Some, like the smallpox vaccine on one exposure generates a very high response that lasts for many years so you don't need a boost.

有一些疫苗,比如接触一次天花疫苗后,人体就能产生高水平的免疫应答,并持续很多年,所以无需再次接种

耶鲁公开课 - 生物医学工程探索课程节选

Barth wrote a famous essay just the year before these stories came out all in one volume. They had been written over a series of years, got a lot of exposure--called "The Literature of Exhaustion."

在写完这一卷故事的前一年,巴斯写了一篇著名的论文，在60年代，叫《枯竭的文学》

耶鲁公开课 - 1945年后的美国小说课程节选

We don't have the records, because people get lung cancer after 30 years of exposure - maybe 40 years.

BBC: News Online

But there is no telling how that might change after seven years of exposure of the ACS to the public.

WSJ: Census Gets Questions on Its Mandatory Queries

He said it was difficult to estimate the true effect because cancer may develop only years after exposure to air pollution.

BBC: Traffic