* Simple: The documentary about the Amazon rainforest was fascinating.
* Descriptive: The intricate details of the ancient Egyptian hieroglyphics were fascinating.
* Comparative: The history of the Roman Empire is far more fascinating than I expected.
* With a preposition: I found myself fascinated by the way she played the violin.
* In a question: Is it fascinating to you that some animals can see ultraviolet light?
You can also use "fascinating" with different parts of speech, such as:
* Adverb: It's fascinatingly complex, but I can't stop looking at it.
* Noun: The fascinating world of quantum physics opened my eyes to a new perspective.