◎ 题干
The country has already sent up three unmanned spacecrafts, the most recent ________at the end of last March.
[     ]
A. has been launched    
B. having been launched  
C. being launched    
D. to be launched
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◎ 解析
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◎ 知识点
    根据n多题专家分析,试题“The country has already sent up three unmanned spacecrafts, the most recent ________at the end of last March. [ ]A. has been launchedB. having been launched C…”主要考查了你对  【现在分词的被动式】【现在分词的完成式】  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。