Consider the following premises. t_1 -> t. q_2 and s. q_2 -> t_1. Can we infer t from them?
 From q_2 and s we can infer q_2. From q_2 -> t_1, t_1 -> t we can infer q_2 -> t. Finally, from q_2 -> t, q_2 we can infer t. Therefore, the answer is yes.