(S (S (PP-SBJ (NP (PP (BASENP (NN 屋根)) (IN の)) (NN 陥没)) (IN は)) (VP (ADVP (RB ほぼ)) (VP (SBAR (S (PP-SBJ (NP (PP (BASENP (NN 大量)) (IN の)) (NN 降雪)) (IN が)) (VP (BASENP (NN 原因)) (VP (MDV だっ) (VP (MD た))))) (INQT と)) (VP (VBO み) (VP (VB られる)))))) (PERIOD 。))
屋根 の 陥没 は ほぼ 大量 の 降雪 が 原因 だっ た と み られる 。
The reason for the cave-in of the roof was most likely massive snowfalls .