Sandy, Sam, and Steve are observing a cat in the distance. The cat is eating something but it\textquotesingle s hard to tell what it is.  Sandy says:"The cat is eating fish."  Sam says:"I agree with Sandy!"  Steve says: "The cat is eating meat."  Then they come closer and realize only one of them guessed right.  The cat is eating . 
Overseas Competition->Knowledge Point->Counting Modules->Permutations and Combinations->Combinations
We can directly find that Sandy\textquotesingle s point and Sam\textquotesingle s point are identical,so both of them tell lies.Therefore, Steve tells the truth. 