The country has already sent up three unmanned spacecraft, the most recent _____

题型：不详难度：来源：

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

句意为：这个国家已经发射了三艘无人驾驶宇宙飞船，最近的一艘于去年三月底发射。A项使后半部分成为一个分句．但两个分句之间无关连词，故排除；B项表示该动作已
被完成；C项表示该动作正在被完成；D项表示该动作将要被完成．从时间状语可知．答案应该选B。