What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is raining if and only if Charles is excited. Linda is a mechanic if and only if it is raining. Linda is a mechanic or Barbara is making tea. Charles is not excited.
If it rains, then Charles is excited. If Linda were a mechanic, then it is raining. If Charles were excited, then it is raining. If it rains, then Linda is a mechanic. It is not raining.