问题描述:
悬赏金豆25 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 我觉得是单数我选A 答案说选B
A. has been launched
B. having been launched
C. being launched
D. to be launched 我觉得是单数我选A 答案说选B
问题解答:
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