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deeply; keenly; severely; completely; utterly
intently; carefully; closely; attentively
今回の失敗でつくづく自分が嫌になった。
I became deeply disgusted with myself after this failure.
彼の顔をつくづく眺めて考え込んでいた。
I was gazing at his face intently, lost in thought.
今日はつくづく運が悪いと思った。
I keenly felt I was unlucky today.