chemical chop

例句：

1. 1. The new drug is designed to treat cancer, but it's not yet approved for use in humans.
   这款新药旨在治疗癌症，但尚未获得人类使用批准。
2. 2. Chemical reactions occur when atoms rearrange to form new compounds.
   化学反应发生在原子重新排列以形成新化合物的过程中。
3. 3. The chemical composition of the substance was determined using a mass spectrometer.
   该物质的化学成分是通过质谱仪测定的。