题目内容
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:B
解析:
解析:
|
考查独立主格结构,根据后面的时间状语可知应用 v.-ing形式的完成式。 |
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