◎ 题干
---Has Tom finished his homework?
---I don’t know.  But he _________ it the whole morning.
A.didB.doesC. was doingD. is doing
◎ 答案
查看答案
◎ 解析
查看解析
◎ 知识点
    根据n多题专家分析,试题“---Has Tom finished his homework?---I don’t know. But he _________ it the whole morning. A.didB.doesC. was doingD. is doing…”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。