Emphasizing the doer of an action with "you"

由 is used to emphasize who is the doer or initiator of an action. It has a formal tone, and is a little like the passive in English, where we might say: "this project was completed by Andy"

The structure is:

Noun + 由 + person + verb

Here are some examples:

• 会议 由 王总 主持，肯定 很 无聊，咱们 准备 睡觉 吧！
• 这 件 事 由 我 负责。
• 这 不 是 由 你 决定，别 干涉。