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together with; as X, then Y (e.g. as we age we gain wisdom, as wine matures it becomes more valuable, etc.)
春の訪れとともに花が咲き始めた。
Together with the arrival of spring, the flowers began to bloom.
年を取るとともに健康の大切さを知る。
As we age, we learn to value our health.
時代とともに価値観も変わっていく。
Values change along with the times.