(S (S (SBAR (S (PP-SBJ (NP (PP (BASENP (NN 落石)) (IN の)) (NN 原因)) (IN は)) (ADJP (NN 不明) (MD だ))) (INCON が)) (COMMA 、) (S (PP-SBJ (BASENP (NN 警察)) (IN は)) (VP (SBAR (S (PP-SBJ (NP (S (PP-SBJ (BASENP (NN 崖) (NN 崩れ)) (IN が)) (VP (VBV 起こり) (MDP (NN そう) (MDO な)))) (NN 兆候)) (IN は)) (ADJP (JJV 無かっ) (VP (MD た)))) (INQT と)) (VP (VP (VBV 述べ) (INTE て)) (VP (VB いる)))))) (PERIOD 。))
落石 の 原因 は 不明 だ が 、 警察 は 崖 崩れ が 起こり そう な 兆候 は 無かっ た と 述べ て いる 。
The cause of the rock fall is unknown , but police have said that there had been no prior signs that the cliff was unstable .