Consider the following premises. p_11 -> q_11. t_4 -> ~s_2. ~p_11 -> s_2. ~q_11. Can we infer ~t_4 from them?
 From p_11 -> q_11, ~q_11 we can infer ~p_11. From ~p_11 -> s_2, ~p_11 we can infer s_2. Finally, from t_4 -> ~s_2, s_2 we can infer ~t_4. Therefore, the answer is yes.