What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If David were an astronaut, then John is sleeping. If Michael were a carpenter, then David is an astronaut. If Susan makes tea, then Michael is a carpenter. If John sleeps, then Susan is making tea.
If David were an astronaut, then Susan is making tea. If Michael were a carpenter, then John is sleeping. If Susan makes tea, then David is an astronaut. If John sleeps, then Michael is a carpenter.