風邪(かぜ) kazeで de彼(かれ)の() kareno味(み)覚(かく) mikakuは wa鈍(にぶ)く() nibukuなっていた natteita。 The cold had dulled his sense of taste. Literal Cold [cause-で] his taste [topic-は] dull became-had. 味覚は鈍くなっていた — 味覚 (taste sense) + 鈍い (dull) in the change-of-state ~くなっていた (had become dull). で marks the cold as the cause. healthillness/coldで (cause/reason)
風邪(かぜ) kazeで de彼(かれ)の() kareno味(み)覚(かく) mikakuは wa鈍(にぶ)く() nibukuなっていた natteita。 The cold had dulled his sense of taste. Literal Cold [cause-で] his taste [topic-は] dull became-had. 味覚は鈍くなっていた — 味覚 (taste sense) + 鈍い (dull) in the change-of-state ~くなっていた (had become dull). で marks the cold as the cause. healthillness/coldで (cause/reason)