List for each of the following statements the free and bound variable identifiers.
1. local y in {p x y} end
2. {p x y} local y in {x p y} end
3. proc {q x} local y in {p z y} end end
4. proc {f n} local m in {f n m} end end
5. case x of f(y) then {p y} else {q y} end