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since
for the past ... (e.g. ten years)
this person; this gentleman; this lady
日本に来てこのかた、一度も帰国していない。
Since coming to Japan, I have not returned home once.
引退してこのかた、畑仕事に生きがいを見つけた。
Since retiring, I have found meaning in farming.
転職してこのかた気持ちが楽になった。
Since changing jobs, I have felt more at ease.