Consider the following premises. There is at least one x_10 for which x_10 is an electrician if and only if x_10 will climb a mountain. For all x_10, if x_10 were an electrician, then x_10 is an office clerk. For all x_10, x_10 is not an office clerk. Can we infer the following from them? There is at least one x_10 for which x_10 will not climb a mountain.
 From the fact that there is at least one x_10 for which x_10 is an electrician if and only if x_10 will climb a mountain we can infer that there is at least one x_10 for which if x_10 climbs a mountain, then x_10 is an electrician. From the fact that there is at least one x_10 for which if x_10 climbs a mountain, then x_10 is an electrician, and that for all x_10, if x_10 were an electrician, then x_10 is an office clerk we can infer that there is at least one x_10 for which if x_10 climbs a mountain, then x_10 is an office clerk. Finally, from the fact that there is at least one x_10 for which if x_10 climbs a mountain, then x_10 is an office clerk, and that for all x_10, x_10 is not an office clerk we can infer that there is at least one x_10 for which x_10 will not climb a mountain. Therefore, the answer is yes.