Consider the following premises. For all z, if z sleeps, then z is playing a game. For all z, if z plays a game, then z is sleeping. There is at least one z for which z will not sleep. For all z, z will play tennis if and only if z will play a game. Can we infer the following from them? For all z, z will play tennis.
 From the fact that for all z, if z sleeps, then z is playing a game, and that for all z, if z plays a game, then z is sleeping we can infer that for all z, z will sleep if and only if z will play a game. From the fact that for all z, z will sleep if and only if z will play a game, and that there is at least one z for which z will not sleep we can infer that there is at least one z for which z will not play a game. Finally, from the fact that for all z, z will play tennis if and only if z will play a game, and that there is at least one z for which z will not play a game we can infer that there is at least one z for which z will not play tennis, which contradicts that For all z, z will play tennis. Therefore, the answer is no.