33．Only after he had spent several nights working on the math problemto wonder whether the
33．Only after he had spent several nights working on the math problemto wonder whether the
发布时间：2020-08-16 06:30:28
33．Only after he had spent several nights working on the math problem to wonder whether the problem was wrongly set． A. did he begin B. he began C. he did begin D. began he
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(答案→)A. did he begin B. he began C. he did begin D. began he 解析：可联系答.案.网客服索取。