(S (S (SBAR (S (PP-SBJ (BASENP (ADJP (NN 正確) (MDO な)) (NN 原因)) (IN は)) (ADJP (NN 不明) (MD だ))) (INCON が)) (COMMA 、) (S (PP (BASENP (NN 目撃) (NN 者)) (INP (IN に) (VB よる) (INCON と))) (COMMA 、) (S (S (PP-SBJ (NP (S-REL-NSBJ (VP (PP-OBJ (BASENP (NN 波)) (IN を)) (VP (VBV 受け) (VP (MD た))))) (NN 船)) (IN が)) (VP (ADVP (RB 突然)) (VP (PP (BASENP (NN 左)) (IN に)) (VBV 傾き)))) (COMMA 、) (S (PP-SBJ (NP (PP (SBAR (S (PP-SBJ (BASENP (NN 乗客)) (IN は)) (VP (PP (NP (PP (BASENP (NN 船)) (IN の)) (NN 片側)) (IN に)) (VP (VP (VBV 倒れ) (INTE て)) (VP (VBV 行っ) (VP (MD た)))))) (INQT と)) (IN の)) (NN 示唆)) (IN も)) (VP (VB ある)))))) (PERIOD 。))
正確 な 原因 は 不明 だ が 、 目撃 者 に よる と 、 波 を 受け た 船 が 突然 左 に 傾き 、 乗客 は 船 の 片側 に 倒れ て 行っ た と の 示唆 も ある 。
The exact cause is unknown - suggestions from eyewitnesses include the boat suddenly turning left , being hit by a wave , and many of the passengers moving to one side of the boat together .