Question

（2011·河南郑州四中第一次调研）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

Answer 1

B考查独立主格结构。根据the end of last March可知动作已经发生，故用现在分词的完成时，因句中的逗号，后用独立主格结构。