(S (S (NP (BASENP (NNP International) (NNP Labor) (NNP Day)) (PRN (COMMA ,) (NP (CC or) (BASENP (NNP May) (NNP Day))) (COMMA ,))) (VP (VBZ has) (VP (VBN been) (VP (VBN marked) (PP (IN by) (NP (BASENP (NNS protests)) (PP (IN throughout) (BASENP (NNP Switzerland))))))))) (PERIOD .))