一个英语句子的结构分析-----------------务必高手帮忙33、The country has already sent up three unmanned spacecraft,the most recent  having been launched  at the end of last March.这个句子是省略句,请补充完整,

问题描述:

一个英语句子的结构分析-----------------务必高手帮忙
33、The country has already sent up three unmanned spacecraft,the most recent  having been launched  at the end of last March.
这个句子是省略句,请补充完整,