Test
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Fact: A gazelle is fast
Q: Is a gazelle slow?

A: No
A: No, it is fast
A: No, it's fast
A: No, a gazelle is fast
A: No, fast
A: No, it's fast, not slow

Not an answer: Yes

Example solution
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Fact: Fast is not slow
Rule: Y is not Z => Z is not Y
Rule: a X is Y & Y is not Z => a X is not Z
Rule: is X Y? & X is not Y => no