Consider the following premises. For all x_8, if x_8 drinks water, then x_8 is not taking a plane. For all x_8, x_8 will take a plane if and only if x_8 will sleep. For all x_8, x_8 will sleep. Can we infer the following from them? There is at least one x_8 for which x_8 will drink water.
 From the fact that for all x_8, x_8 will take a plane if and only if x_8 will sleep we can infer that for all x_8, if x_8 sleeps, then x_8 is taking a plane. From the fact that for all x_8, if x_8 sleeps, then x_8 is taking a plane, and that for all x_8, x_8 will sleep we can infer that for all x_8, x_8 will take a plane. Finally, from the fact that for all x_8, if x_8 drinks water, then x_8 is not taking a plane, and that for all x_8, x_8 will take a plane we can infer that for all x_8, x_8 will not drink water, which contradicts that There is at least one x_8 for which x_8 will drink water. Therefore, the answer is no.