Consider the following premises. For all x_1, if x_1 takes a plane, then x_1 is a carpenter. For all x_1, if x_1 were a carpenter, then x_1 is sleeping. There is at least one x_1 for which x_1 will sleep if and only if x_1 will take a plane. Can we infer the following from them? There is at least one x_1 for which if x_1 sleeps, then x_1 is taking a plane.
 From the fact that for all x_1, if x_1 takes a plane, then x_1 is a carpenter, and that for all x_1, if x_1 were a carpenter, then x_1 is sleeping we can infer that for all x_1, if x_1 takes a plane, then x_1 is sleeping. Finally, from the fact that there is at least one x_1 for which x_1 will sleep if and only if x_1 will take a plane we can infer that there is at least one x_1 for which if x_1 sleeps, then x_1 is taking a plane. Therefore, the answer is yes.