3 sentences

1. 硫是一种黄色的化学元素。

   liú shì yī zhǒng huáng​sè de huà​xué yuán​sù.

   Sulfur is a yellow chemical element.

   Source: Dong Chinese Dictionary

2. 学生们正在实验室里观察不同化学元素的反应。

   xué​sheng men zhèng​zài shí​yàn​shì lǐ guān​chá bù​tóng huà​xué yuán​sù de fǎn​yìng.

   The students are observing the reactions of different chemical elements in the laboratory.

   Source: Dong Chinese Dictionary

3. 通过分析恒星光的谱，天文学家能够确定该星体中包含的化学元素。

   tōng​guò fēn​xī héng​xīng guāng de pǔ, tiān​wén​xué​jiā néng​gòu què​dìng gāi xīng​tǐ zhōng bāo​hán de huà​xué yuán​sù.

   By analyzing the spectrum of starlight, astronomers can determine the chemical elements contained within the star.

   Source: Dong Chinese Dictionary