Consider the following premises. For all x_2, if x_2 sleeps, then x_2 is happy. For all x_2, if x_2 were happy, then x_2 is working. For all x_2, if x_2 works, then x_2 is sleeping. Can we infer the following from them? For all x_2, if x_2 were happy, then x_2 is sleeping.
Yes.