Consider the following premises. For all y, y will not make tea. If Robert were an astronaut, then it is sunny. Richard is making tea if and only if it is sunny. Can we infer the following from them? Robert is an astronaut.
 From the fact that for all y, y will not make tea we can infer that Richard is not making tea. From the fact that Richard is making tea if and only if it is sunny, and that Richard is not making tea we can infer that it is not sunny. Finally, from the fact that if Robert were an astronaut, then it is sunny, and that it is not sunny we can infer that Robert is not an astronaut, which contradicts that Robert is an astronaut. Therefore, the answer is no.