The country has already sent up three unmanned spacecraft,the most recent ______at the end of last March .

问题描述:

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
选B 解析上说此句前后句没连词,只有逗号是不能连接两个句子的,所以后边the most recent ______ at the end of last March就是独立主格的形式了,在句中做伴随状语

这个是独立主格结构 解释是正确的首先一个句子在没有连词的情况下,只能有一个谓语动词.着句话前面已经有了has already sent up做谓语动词了,逗号不能连接两个完整的句子,所以A答案是最迷惑的,如果是分号或者有个连词...