Consider the following premises. Mary is playing tennis if and only if William is excited. William is not excited. It is not raining. Karen is a lawyer if and only if it is raining. Can we infer the following from them? Karen is a lawyer.
 From the fact that Mary is playing tennis if and only if William is excited, and that William is not excited we can infer that Mary is not playing tennis. Finally, from the fact that Karen is a lawyer if and only if it is raining, and that it is not raining we can infer that Karen is not a lawyer, which contradicts that Karen is a lawyer. Therefore, the answer is no.