Consider the following premises. For all x_4, x_4 is a poet and x_4 will listen to a song. For all x_4, x_4 will take a plane. Can we infer the following from them? There is at least one x_4 for which x_4 is not a poet.
 From the fact that for all x_4, x_4 is a poet and x_4 will listen to a song we can infer that for all x_4, x_4 is a poet. From the fact that for all x_4, x_4 will take a plane, and that for all x_4, x_4 is a poet we can infer that for all x_4, x_4 will take a plane and x_4 is a poet. Finally, from the fact that for all x_4, x_4 will take a plane and x_4 is a poet we can infer that for all x_4, x_4 will take a plane, which contradicts that There is at least one x_4 for which x_4 is not a poet. Therefore, the answer is no.