(S (S (S (BASENP (NNP Wikipedia)) (VP (VBZ has) (VP (VBN been) (VP (VP (VBN blocked) (ADVP (RB twice))) (ADVP (RB before)))))) (COMMA ,) (NP (BASENP (DT the) (NN first)) (PP (IN from) (BASENP (NN 2-21) (NNP June) (NN 2004))) (COMMA ,) (PP (JJ due) (PP (TO to) (NP (BASENP (DT the) (JJ 15th) (NN anniversary)) (PP (IN of) (BASENP (DT the) (NNP Tian) (POS `) (NNP anmen) (NNP Square) (NNP Incident)))))))) (PERIOD .))