He mentions books and articles written at that time , and into the 20th century too , that excoriate mongrels and other weaklings for contaminating the purity of bloodlines .
他提到,从那个时候一直到20世纪,有很多书籍和文章都指责杂交狗和其他病狗污染了纯种狗的血统。
But every previous reported success turned out to be a case of modern bacteria contaminating the amber during the extraction process .
但过去宣布成功的先行者们最后无不发现,在他们的实验过程中实际上是现代的细菌污染了琥珀的样本。
Pollution means contaminating the earth 's environment with materials that harm people 's health and lower their quality of life .
污染意味着(指的是)用损害人类健康和降低人们生命质量的物质去破坏地球的环境。
But other scientists countered that water often moves through salt deposits , potentially contaminating the ancient salt crystals with younger microbes .