Not until he retired from teaching three years ago having a holiday abroad. A. he had cons

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A. he had considered
B. had he considered
C. he considered
(答案→)D. did he consider
解析：考察倒装句。Not until引导时间状语，放在句首的时候，后面使用部分倒装的形式，排除AC；根据句意本题使用一般过去时，句意：知道三年前他退休，他才考虑出国度假。