Consider the following premises. For all x_7, if x_7 were a writer, then x_7 is not a doctor. For all x_7, x_7 is a doctor. If Jennifer were a nurse, then Charles is a writer. Can we infer the following from them? Jennifer is a nurse.
 From the fact that for all x_7, if x_7 were a writer, then x_7 is not a doctor, and that for all x_7, x_7 is a doctor we can infer that for all x_7, x_7 is not a writer. From the fact that for all x_7, x_7 is not a writer we can infer that Charles is not a writer. Finally, from the fact that if Jennifer were a nurse, then Charles is a writer, and that Charles is not a writer we can infer that Jennifer is not a nurse, which contradicts that Jennifer is a nurse. Therefore, the answer is no.