I knew I had made a mistake.

我知道自己犯了个错误。

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I conceded that I had made a mistake.

我承认我犯了一个错误。

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I recognized that I had made a mistake.

我认识到自己犯了一个错误。

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"I consider myself a pro among pros, but I had to consider the outside possibility that I had made a mistake, " he told reporters at the Tokyo Stock Exchange.

BBC: NEWS | Business | Japanese fund chief is arrested

Again and again, the truth was confronting me: I was a born townie, and I had made a dreadful mistake in coming here.

NEWYORKER: Fjord of Killary

The orchestra broke up laughing, for in five years I had never made a noticeable mistake.

WSJ: Cello's Golden Age Comes to a Close | J��nos Starker | By Stuart Isacoff