Consider the following premises. If Michael were an astronaut, then John is playing squash. For all x_6, x_6 will write a letter or x_6 is a server. If David were a server, then John is playing squash. David is not writing a letter or Michael is an astronaut. Can we infer the following from them? If we can, name the inference rule being used: It is cloudy.
We cannot infer that from the premises. Therefore the answer is no.