A + 组成 + B / 由 + A + 组成
The verb 组成 (zǔchéng) means "to form," "to compose," or "to make up." It is used to describe how individual parts come together to create a whole, and can appear in both active constructions (A and B form C) and passive ones (C is composed of A and B).
这个委员会由十二名成员组成。
Zhège wěiyuánhuì yóu shí'èr míng chéngyuán zǔchéng.
This committee is composed of twelve members.
水是由氢和氧两种元素组成的。
Shuǐ shì yóu qīng hé yǎng liǎng zhǒng yuánsù zǔchéng de.
Water is composed of two elements: hydrogen and oxygen.
我们组成了一个五人小组来负责这个项目。
Wǒmen zǔchéngle yí gè wǔ rén xiǎozǔ lái fùzé zhège xiàngmù.
We formed a five-person team to be in charge of this project.