Consider the following premises. David is working. It is snowing. If Thomas were a lawyer, then David is not working. Can we infer the following from them? If we can, name the inference rule being used: Thomas is a lawyer.
 From the fact that David is working, and that it is snowing we can infer that David is working and it is snowing via conjunction. From the fact that David is working and it is snowing we can infer that David is working via simplification. Finally, from the fact that if Thomas were a lawyer, then David is not working, and that David is working we can infer that Thomas is not a lawyer via modus tollens, which contradicts that Thomas is a lawyer. Therefore, the answer is no.