◎ 题干
The country has already sent up three unmanned spacecraft, the most recent ______________  at the
end of last March.   
[     ]
A.  has been launched  
B. having been launched  
C. being launched  
D.  to be launched
◎ 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“The country has already sent up three unmanned spacecraft, the most recent ______________at theend of last March.[ ]A.has been launchedB. having been launched…”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。