Consider the following premises. forall y: T(y). forall x: W(x). Can we infer exists y: W(y) and T(y) from them? If possible, name the inference rules being used at each step.
 From forall x: W(x) we can infer W(a_10) via universal instantiation. From W(a_10) we can infer exists y: W(y) via existential generalization. Finally, from exists y: W(y), forall y: T(y) we can infer exists y: W(y) and T(y) via existential conjunction. Therefore, the answer is yes.