Consider the following premises. For all x_11, x_11 will play squash if and only if x_11 is a sailor. For all z_4, z_4 will drink water. Susan is not a sailor. Can we infer the following from them? Susan is playing squash.
 From the fact that for all z_4, z_4 will drink water we can infer that Barbara is drinking water. From the fact that for all x_11, x_11 will play squash if and only if x_11 is a sailor we can infer that Susan is playing squash if and only if Susan is a sailor. Finally, from the fact that Susan is playing squash if and only if Susan is a sailor, and that Susan is not a sailor we can infer that Susan is not playing squash, which contradicts that Susan is playing squash. Therefore, the answer is no.