What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one x_13 for which x_13 will play squash if and only if x_13 is a nurse. For all x_13, x_13 will listen to a song if and only if x_13 is a nurse. For all x_13, x_13 will not listen to a song. For all x_13, if x_13 writes a letter, then x_13 is a nurse. For all x_13, if x_13 listens to a song, then x_13 is writing a letter.
For all x_13, if x_13 listens to a song, then x_13 is a nurse. For all x_13, if x_13 listens to a song, then x_13 is a nurse. There is at least one x_13 for which if x_13 plays squash, then x_13 is a nurse. For all x_13, if x_13 were a nurse, then x_13 is listening to a song. There is at least one x_13 for which if x_13 were a nurse, then x_13 is playing squash. For all x_13, x_13 is not a nurse.