(S (S (BASENP (DT The) (NNP Trident) (NN missile) (NN system)) (VP (VBZ is) (VP (VBN carried) (PP (IN in) (NP (BASENP (NN four) (JJ nuclear-powered) (NNP Vanguard) (NN class) (NNS submarines)) (COMMA ,) (SBAR (WHNP (BASENP (DT the) (JJ first)) (WHPP (IN of) (WHNP (WDT which)))) (S (VP (VBD was) (VP (VBN commissioned) (PP (IN in) (BASENP (NNP August) (NN 1993)))))))))))) (PERIOD .))