Sentence examples for a keen from inspiring English sources

The phrase "a keen" can be correct and usable in written English, but it would usually need to be followed by a noun or adjective to make a complete sentence.
Some examples of how it could be used are: - "He has a keen eye for detail." (adjective) - "She is a keen supporter of the arts." (adjective) - "A keen understanding of mathematics is essential for this job." (noun) - "The crowd erupted into a keen cheer as their team scored the winning goal." (noun).