Consider the following premises. James is a taxi driver if and only if Elisabeth is excited. For all x_1, x_1 is not a taxi driver. Elisabeth is excited if and only if Robert is working. Can we infer the following from them? Robert is working.
 From the fact that for all x_1, x_1 is not a taxi driver we can infer that James is not a taxi driver. From the fact that James is a taxi driver if and only if Elisabeth is excited, and that James is not a taxi driver we can infer that Elisabeth is not excited. Finally, from the fact that Elisabeth is excited if and only if Robert is working, and that Elisabeth is not excited we can infer that Robert is not working, which contradicts that Robert is working. Therefore, the answer is no.