Consider the following premises. There is at least one x for which x will climb a mountain. For all x, if x were an electrician, then x is not climbing a mountain. For all x, x is an electrician or x will not take a plane. Can we infer the following from them? If we can, name the inference rule being used: For all x, x will take a plane.
 From the fact that for all x, x is an electrician or x will not take a plane we can infer that for all x, if x takes a plane, then x is an electrician via universal rewriting. From the fact that for all x, if x were an electrician, then x is not climbing a mountain, and that there is at least one x for which x will climb a mountain we can infer that there is at least one x for which x is not an electrician via existential modus tollens. Finally, from the fact that for all x, if x takes a plane, then x is an electrician, and that there is at least one x for which x is not an electrician we can infer that there is at least one x for which x will not take a plane via existential modus tollens, which contradicts that For all x, x will take a plane. Therefore, the answer is no.