Converting statements with quantifiers I'm having a little trouble understanding quantifiers and therefore doubting all my study answers. Since there is no where to check if the answers are correct, I'm very very worried I am just practicing incorrectly. So I've set up two examples with what I think the answers are.
It would be brilliant if you could confirm if I am correct or not so I could use these answers as a base to check my other answers. If I am incorrect, it would be awesome if you could point me the right direction!
Example 1: Nobody except Jay and Mike is walking home.
My answer: ∀x [walking home(x) ∧ [¬ mike(x) ∧ ¬ Jay(x)]]    
Example 2: There is a time to watch, and a time to bluff; a time to fold, and a time to check. 
My answer: ∀x,y,z,v [watch(x) ∧ bluff(y) ∧ fold (z) ∧ check(v)] I chose ∀ since I've always seen it as another way of saying "always" but I could be wrong.


Nobody except Jay and Mike is walking home.

We would normally translate names with names (constants), not predicates. Thus, assuming the domain of quantification is people, and using '$j$' as a constant to denote Jay and '$m$' as a constant to denote Mike, then 
$$\forall x(Wx \to (x = j \lor x= m))$$
would be neat -- take anyone you like, if they are walking home then they are either Jay or Mike. Or equivalently, but perhaps somewhat less prettily, we could have
$$\neg\exists x(Wx \land (\neg x = j \land \neg x = m))$$
For the other question, as others explain, you need an existential quantifier to render the natural reading of 'There is a time ...'.
