◎ 题干
When the teacher came into the classroom, the students ____ in groups.
A.workB.have workedC.were workingD.are working
◎ 答案
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◎ 解析
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◎ 知识点
    根据n多题专家分析,试题“When the teacher came into the classroom, the students ____ in groups.A.workB.have workedC.were workingD.are working…”主要考查了你对  【一般现在时】【过去进行时】【过去完成进行时】  等知识点的理解和应用能力。关于这些知识点的“档案”,你可以点击相应的链接进行查看和学习。