(S (S (PP (IN At) (BASENP (NNP Buckingham) (NNP Palace))) (COMMA ,) (S (BASENP (NNP Queen) (NNP Elizabeth) (NNP II)) (VP (VP (VP (VBD stood) (PP (IN on) (BASENP (DT the) (NN forecourt)))) (PP (IN in) (BASENP (NN silence)))) (COMMA ,) (S (VP (VBN accompanied) (PP (IN by) (BASENP (NNP Foot) (NNP Guards)))))))) (PERIOD .))