Consider the following premises. For all x_12, if x_12 writes a letter, then x_12 is reading a book. For all x_12, x_12 is a cashier and x_12 will play tennis. There is at least one x_12 for which if x_12 were a cashier, then x_12 is writing a letter. Can we infer the following from them? For all x_12, x_12 will not read a book.
 From the fact that for all x_12, x_12 is a cashier and x_12 will play tennis we can infer that for all x_12, x_12 is a cashier. From the fact that there is at least one x_12 for which if x_12 were a cashier, then x_12 is writing a letter, and that for all x_12, x_12 is a cashier we can infer that there is at least one x_12 for which x_12 will write a letter. Finally, from the fact that for all x_12, if x_12 writes a letter, then x_12 is reading a book, and that there is at least one x_12 for which x_12 will write a letter we can infer that there is at least one x_12 for which x_12 will read a book, which contradicts that For all x_12, x_12 will not read a book. Therefore, the answer is no.