Consider the following premises. For all x_11, x_11 will sleep if and only if x_11 will read a book. For all x_11, x_11 will read a book if and only if x_11 will sleep. Can we infer the following from them? If Susan sleeps, then Susan is reading a book.
 From the fact that for all x_11, x_11 will read a book if and only if x_11 will sleep we can infer that for all x_11, if x_11 sleeps, then x_11 is reading a book. From the fact that for all x_11, x_11 will sleep if and only if x_11 will read a book we can infer that for all x_11, if x_11 reads a book, then x_11 is sleeping. From the fact that for all x_11, if x_11 reads a book, then x_11 is sleeping, and that for all x_11, if x_11 sleeps, then x_11 is reading a book we can infer that for all x_11, x_11 will read a book if and only if x_11 will sleep. From the fact that for all x_11, x_11 will read a book if and only if x_11 will sleep we can infer that Susan is reading a book if and only if Susan is sleeping. Finally, from the fact that Susan is reading a book if and only if Susan is sleeping we can infer that if Susan sleeps, then Susan is reading a book. Therefore, the answer is yes.