Thecountryhasalreadysentupthreeunmannedspacecraft,themo...

问题详情：

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

【回答】

B

知识点：主谓一致

题型：选择题