Consider the following premises. There is at least one x_10 for which x_10 is not a police officer. For all x_10, x_10 is a police officer if and only if x_10 will read a book. For all x_10, x_10 will read a book or x_10 is not a nurse. Can we infer the following from them? There is at least one x_10 for which x_10 is not a nurse.
 From the fact that for all x_10, x_10 is a police officer if and only if x_10 will read a book, and that there is at least one x_10 for which x_10 is not a police officer we can infer that there is at least one x_10 for which x_10 will not read a book. From the fact that for all x_10, x_10 will read a book or x_10 is not a nurse we can infer that for all x_10, if x_10 were a nurse, then x_10 is reading a book. Finally, from the fact that for all x_10, if x_10 were a nurse, then x_10 is reading a book, and that there is at least one x_10 for which x_10 will not read a book we can infer that there is at least one x_10 for which x_10 is not a nurse. Therefore, the answer is yes.