Consider the following premises. For all z, if z drinks water, then z is writing a letter. There is at least one z for which z will not read a book. For all z, if z reads a book, then z is drinking water. For all z, if z writes a letter, then z is reading a book. For all z, z will play squash if and only if z will write a letter. Can we infer the following from them? For all z, z will play squash.
 From the fact that for all z, if z reads a book, then z is drinking water, and that for all z, if z drinks water, then z is writing a letter we can infer that for all z, if z reads a book, then z is writing a letter. From the fact that for all z, if z reads a book, then z is writing a letter, and that for all z, if z writes a letter, then z is reading a book we can infer that for all z, z will read a book if and only if z will write a letter. From the fact that for all z, z will read a book if and only if z will write a letter, and that there is at least one z for which z will not read a book we can infer that there is at least one z for which z will not write a letter. Finally, from the fact that for all z, z will play squash if and only if z will write a letter, and that there is at least one z for which z will not write a letter we can infer that there is at least one z for which z will not play squash, which contradicts that For all z, z will play squash. Therefore, the answer is no.