Consider the following premises. It is cloudy or David is not happy. If it is sunny, then it is not cloudy. David is happy. Can we infer the following from them? If we can, name the inference rule being used: It is sunny.
 From the fact that it is cloudy or David is not happy we can infer that if David were happy, then it is cloudy via rewriting. From the fact that if David were happy, then it is cloudy, and that David is happy we can infer that it is cloudy via modus ponens. Finally, from the fact that if it is sunny, then it is not cloudy, and that it is cloudy we can infer that it is not sunny via modus tollens, which contradicts that It is sunny. Therefore, the answer is no.