(S (S (BASENP (DT Some) (NNS protesters)) (VP (VBD taunted) (NP (BASENP (NN riot) (NNS police)) (COMMA ,) (SBAR (WHNP (WP who)) (S (VP (VBD responded) (PP (IN with) (BASENP (NN stun) (NNS grenades))))))))) (PERIOD .))