Onlyaftertheyhadperformedhundredsofexperiments_____ins... 国语站 题库 1.95W 大中小设置文字大小 问题详情： Only after they had performed hundreds of experiments _____ in solving the problem.A. did they succeed B. they succeeded C. had they succeeded D. they had succeeded【回答】A知识点：倒装与省略题型：选择题 TAG标签：#
