element toxicity

例句：

1. 1. The study of the elements is essential for understanding the structure of matter.
   研究元素对于理解物质的结构至关重要。
2. 2.The chemical composition of the sample was determined to be primarily composed of carbon and hydrogen.
   样品的化学成分主要是由碳和氢组成的。
3. 3.The toxicity of the substance was evaluated based on its ability to cause harm to humans.
   根据其对人类造成危害的能力，评估了该物质的毒性。