Consider the following premises. There is at least one x_3 for which x_3 will work or x_3 will drink water. For all x_3, x_3 is not a scientist. For all x_3, if x_3 works, then x_3 is a scientist. For all x_3, if x_3 were a scientist, then x_3 is working. Can we infer the following from them? If we can, name the inference rule being used: For all x_3, x_3 will not drink water.
 From the fact that for all x_3, if x_3 were a scientist, then x_3 is working, and that for all x_3, if x_3 works, then x_3 is a scientist we can infer that for all x_3, x_3 is a scientist if and only if x_3 will work via universal biconditional introduction. From the fact that for all x_3, x_3 is a scientist if and only if x_3 will work, and that for all x_3, x_3 is not a scientist we can infer that for all x_3, x_3 will not work via universal biconditional elimination. Finally, from the fact that there is at least one x_3 for which x_3 will work or x_3 will drink water, and that for all x_3, x_3 will not work we can infer that there is at least one x_3 for which x_3 will drink water via existential disjunctive syllogism, which contradicts that For all x_3, x_3 will not drink water. Therefore, the answer is no.