de

de

"De" (的) is a particle used to indicate possession, modification, or association.

In this sentence, 'de' (的) is used as a possessive marker to indicate ownership, linking '我' (I) with '书' (book).

这是我的书。

This is my book.

Here, 'de' (的) is used to form a phrase '跑步的时候' (time of running), linking '跑步' (running) and '时候' (time).

我喜欢跑步的时候听音乐。

I like listening to music while running.

In this example, 'de' (的) connects the adjective '干净' (clean) with the noun '桌子' (table), describing the table.

她有一张干净的桌子。

She has a clean table.