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to judge (on the basis of)
to control; to discipline (oneself); to regulate
彼は自らを厳しく律した。
He strictly disciplined himself.
感情を律して冷静に交渉を進めた。
I controlled my emotions and calmly proceeded with the negotiation.
選手たちは試合前に食事と睡眠を律している。
The athletes regulate their diet and sleep before games.