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

通常由于( )、文件有缺陷或技术性错误等引起的索赔，承包商可以列入利润。

A．工程暂停

B．业主原因

C．工期延长

D．工程变更