safe concentration

例句：

1. 1. The workerswere instructed to maintain a safe concentration of chemicals in the workplace.
   工人被指示在工作场所保持化学物质的安全浓度。
2. 2.The company implemented strict safety measures to ensure a safe concentration of employees.
   公司实施严格的安全措施，以确保员工安全。
3. 3. The research team focused on finding a safe concentration of the drug that would be effective without causing side effects.
   研究团队专注于找到一种药物的安全浓度，既能有效又不会引起副作用。