(S (S (S (BASENP (DT The) (JJ first) (NN attack)) (VP (VBD took) (BASENP (NN place)))) (SBAR (WHADVP (WRB when)) (S (BASENP (DT a) (JJ police-army) (NN convoy)) (VP (VBD was) (VP (VP (VBN hit) (PP (IN by) (BASENP (NN two) (JJ roadside) (NNS bombs)))) (PP (IN in) (NP (BASENP (DT the) (JJ mountainous) (NN region)) (PP (IN near) (BASENP (DT the) (NNP Pakistani-Afghani) (NN border)))))))))) (PERIOD .))