无
中文翻译：Unknown
同义词：
['ppm（parts per million，百万分之一）']
例句：
-
1. The concentration of the pollutant in the water is 0.5 ppm.
水中污染物的浓度为0.5 ppm。
-
2. The soil test showed that the pH level was 6.8, which is within the acceptable range for most crops.
土壤测试显示pH值为6.8，对大多数作物来说是可接受的。
-
3.The manufacturer claims that the product has a ppm level of 100, which meets the safety standards.
制造商声称该产品的ppm水平为100，符合安全标准。