Consider the following premises. For all x_11, x_11 will take a plane. For all x_11, x_11 is excited if and only if x_11 will play tennis. For all x_11, x_11 is excited. For all x_11, if x_11 takes a plane, then x_11 is a server. Can we infer the following from them? For all x_11, x_11 is a server and x_11 will play tennis.
 From the fact that for all x_11, x_11 is excited if and only if x_11 will play tennis we can infer that for all x_11, if x_11 were excited, then x_11 is playing tennis. From the fact that for all x_11, if x_11 takes a plane, then x_11 is a server, and that for all x_11, x_11 will take a plane we can infer that for all x_11, x_11 is a server. From the fact that for all x_11, if x_11 were excited, then x_11 is playing tennis, and that for all x_11, x_11 is excited we can infer that for all x_11, x_11 will play tennis. Finally, from the fact that for all x_11, x_11 is a server, and that for all x_11, x_11 will play tennis we can infer that for all x_11, x_11 is a server and x_11 will play tennis. Therefore, the answer is yes.