Consider the following premises. exists y: W(y) or ~T(y). forall y: R(y) -> W(y). forall y: T(y) or R(y). Can we infer exists y: W(y) from them? If possible, name the inference rules being used at each step.
 From exists y: W(y) or ~T(y) we can infer exists y: T(y) -> W(y) via existential rewriting. Finally, from exists y: T(y) -> W(y), forall y: R(y) -> W(y), forall y: T(y) or R(y) we can infer exists y: W(y) via existential disjunction elimination. Therefore, the answer is yes.