1. Statement of fact:
* Our sun is not completely yellow. (This is the most straightforward and grammatically correct way to state the fact.)
2. Question:
* Our sun, not completely yellow? (This uses a question mark to create a questioning tone, potentially suggesting surprise or disbelief.)
3. Incomplete sentence:
* Our sun, not completely yellow... (This creates a sense of unfinished thought or suspense, leaving the reader to consider the implications.)
4. Emphasized phrase:
* Our sun, not completely yellow! (The exclamation mark adds emphasis and possibly a sense of excitement or revelation.)
The best punctuation choice will depend on the specific context and the desired effect.