Consider the following premises. For all x_7, if x_7 makes tea, then x_7 is an astronaut. There is at least one x_7 for which if x_7 makes tea, then x_7 is an astronaut. For all x_7, if x_7 were an astronaut, then x_7 is making tea. Can we infer the following from them? There is at least one x_7 for which x_7 will make tea if and only if x_7 is an astronaut.
 From the fact that for all x_7, if x_7 were an astronaut, then x_7 is making tea, and that there is at least one x_7 for which if x_7 makes tea, then x_7 is an astronaut we can infer that there is at least one x_7 for which x_7 is an astronaut if and only if x_7 will make tea. From the fact that there is at least one x_7 for which x_7 is an astronaut if and only if x_7 will make tea we can infer that there is at least one x_7 for which if x_7 were an astronaut, then x_7 is making tea. Finally, from the fact that for all x_7, if x_7 makes tea, then x_7 is an astronaut, and that there is at least one x_7 for which if x_7 were an astronaut, then x_7 is making tea we can infer that there is at least one x_7 for which x_7 will make tea if and only if x_7 is an astronaut. Therefore, the answer is yes.