Consider the following premises. For all y, if y takes a plane, then y is a sailor. For all y, y will take a plane. There is at least one y for which y will play squash. Can we infer the following from them? For all y, y will not play squash.
 From the fact that for all y, if y takes a plane, then y is a sailor, and that for all y, y will take a plane we can infer that for all y, y is a sailor. From the fact that there is at least one y for which y will play squash, and that for all y, y is a sailor we can infer that there is at least one y for which y will play squash and y is a sailor. Finally, from the fact that there is at least one y for which y will play squash and y is a sailor we can infer that there is at least one y for which y will play squash, which contradicts that For all y, y will not play squash. Therefore, the answer is no.