1. The usage of the three words "de": "de" is followed by words or words that represent the name of things.
2. Such as the beloved Prime Minister, the kind old man, the boy wearing a hat, precious textbooks, etc.
3. 2. "Di" is followed by words or expressions expressing actions.
4. Such as shouting loudly, singing happily, running desperately, swearing crazily, watching closely, shaking hands again and again, etc.
5. 3. "De" is mostly followed by words or words indicating actions, followed by words or words describing the state of things, indicating how to do things.
6. Such as: walking very fast, trampling badly, barking in pain, skinny, etc.