What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If it is late, then William is an office clerk. If William were an office clerk, then it is late. William is an office clerk if and only if it is snowing.
It is late if and only if William is an office clerk. William is an office clerk if and only if it is late. If William were an office clerk, then it is snowing. If it snows, then William is an office clerk.