Q: If B is a proper subset of C, then C - A does not equal the empty set. Is this statement always true, always false, or sometimes true and sometimes false? Explain.

I get that if B is a proper subset of C, then there must be at least one element within the set C that doesn't belong in set B. And for C - B to take place, I explained that x must be a member of C and can't be a member of A. But I really don't know how to tie these relations together. Am I getting hot or cold?