Consider the following premises. ~u_3. u_3 or w_3. t_4 or q_6. q_6 -> r_6. s -> ~w_3. t_4 -> r_6. Can we infer s from them?
 From u_3 or w_3, ~u_3 we can infer w_3. Finally, from s -> ~w_3, w_3 we can infer ~s, which contradicts s. Therefore, the answer is no.