INTERJENCTION

Interjection:
The part of speech that expresses strong feeling or sudden emotions or sentiment is called interjection or exclamation.

Interjections are not grammatically related to any other part of the sentence.

Example:
- Oh no, I missed the schedule of the class. (express failure)
- Hey! Don’t you hear me? (calling attention)
- Hey! Take it easy. (calling attention)
- Uh, I forget the answer. (Express hesitation)
- Hurrah! We have won the match. (Express joy)
- Wow! She is amazing. (Express surprise)