(S (S (PP-SBJ (BASENP (NN それ)) (IN は)) (VP (PP (PP (NP (NP (PP (BASENP (NN 次)) (IN の)) (NN 夜)) (CC と) (NP (PP (BASENP (NN ２) (NN 週間) (NN 後)) (IN の)) (BASENP (NN ９) (NN 月) (NN ６) (NN 日)))) (IN に)) (IN も)) (VP (VP (VP (NN 観測) (VBO さ)) (VP (VBV れ))) (VP (MD た))))) (PERIOD 。))
それ は 次 の 夜 と 2 週間 後 の 9 月 6 日 に も 観測 さ れ た 。
It was also observed on the next night and two weeks later on September 6 .