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 overcast. William is not climbing a mountain. William is climbing a mountain if and only if it is overcast. If Elisabeth were fast, then it is cloudy. If it is overcast, then Elisabeth is fast.
If it is cloudy, then Elisabeth is fast. If Elisabeth were fast, then it is overcast. If it is overcast, then it is cloudy. If William climbs a mountain, then it is overcast. If it is overcast, then William is climbing a mountain. It is not overcast.