(S (S (S (BASENP (DT The) (NNP UPDF) (NNS forces)) (VP (VBP have) (VP (VBN been) (VP (VBN attacked))))) (SBAR (IN since) (S (VP (VP (VBG arriving) (PP (IN at) (BASENP (NNP Mogadishu)))) (PP (IN on) (BASENP (NNP March) (NN 6))))))) (PERIOD .))