(S (S (BASENP (DT The) (NN employee)) (VP (VBD had) (VP (VBN been) (VP (VBN tutored) (PP (IN on) (SBAR (WHADVP (WRB how)) (S (VP (TO to) (VP (VB distinguish) (BASENP (NNS predators))))))))))) (PERIOD .))