Consider the following premises. If John drinks water, then it is not raining. William is curious. It is raining. John is drinking water if and only if it is sunny. Can we infer the following from them? It is sunny.
 From the fact that if John drinks water, then it is not raining, and that it is raining we can infer that John is not drinking water. Finally, from the fact that John is drinking water if and only if it is sunny, and that John is not drinking water we can infer that it is not sunny, which contradicts that It is sunny. Therefore, the answer is no.