I never forgave her for undermining my instructions. I never let her off the hook, and our relations were never good.

My comments:

Hook refers to the fishhook, the curved device to catch a fish. And when a fish bites and hook and you let it off the hook, you pull the fishhook out of its mouth and let it free.

If you don’t let it off the hook, it’s stuck there, in pain and trouble.

Hence you can infer that if he never lets her off the hook, he means to say that he never forgives her for making a mistake, keep criticizing her.

In short, he never frees her from an obligation.

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本文僅代表作者本人觀點，與本網立場無關。歡迎大家討論學術問題，尊重他人，禁止人身攻擊和發布一切違反國家現行法律法規的內容。

About the author:

Zhang Xin（張欣） has been with China Daily since 1988, when he graduated from Beijing Foreign Studies University. Write him at: zhangxin@chinadaily.com.cn, or raise a question for potential use in a future column.