Not until ________ the exam ________ the importance of doing homework.
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A. had he failed; he realized B. he had failed; did he realize C. he had failed; he realized D. had he failed; did he realize
参考答案:
Never before ___________in greater need of technical experts..
Never before ___________in greater need of technical experts than it is today.A.has Shenyang beenB.Shenyang has beenC.was ShenyangD.Shenyang was