眠(ねむ)っ()て()い()る() nemutteiruよう youだった dattaが ga、本(ほん)当(とう) hontouは wa死(し)ん()で()い()た() shindeita。 He seemed to be sleeping, but in reality he was dead. Literal Sleeping [seemed-ようだった] [but-が], in-reality had-died-[progressive-ていた]. ようだった is the past of ようだ. 本当は ('in truth, in reality') contrasts with the appearance. 死んでいた is the past-state form of 死ぬ — a state-of-death, consistent with Japanese's use of ~ている for resulting states even for 'to die.' deathmysteryようだった (seemed)~ている (resulting state)resultative state of 死ぬ (死んでいる)
眠(ねむ)っ()て()い()る() nemutteiruよう youだった dattaが ga、本(ほん)当(とう) hontouは wa死(し)ん()で()い()た() shindeita。 He seemed to be sleeping, but in reality he was dead. Literal Sleeping [seemed-ようだった] [but-が], in-reality had-died-[progressive-ていた]. ようだった is the past of ようだ. 本当は ('in truth, in reality') contrasts with the appearance. 死んでいた is the past-state form of 死ぬ — a state-of-death, consistent with Japanese's use of ~ている for resulting states even for 'to die.' deathmysteryようだった (seemed)~ている (resulting state)resultative state of 死ぬ (死んでいる)