1) Fighting with Back to river
背水为阵
2) base line level
背景水平
1.
In order to understand base line levels of arsenic in organisms in the Daya Bay, determination and assessment of arsenic concentrations in the organisms collected from 15 stations of the Bay were carried out in 1993.
为了了解大亚湾海洋生物体Ａｓ含量的背景水平，１９９３年在大亚湾１５个测站采集了海洋生物样品，对其Ａｓ含量进行了测定和评价。