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