We( )six astronaut into space in the past few years.A.send B
We( )six astronaut into space in the past few years.A.send B.sent C.have launch D.launched 选哪个?不是应该用现在完成时吗?还选B? 还有一个:The flight was canceled because ofthe heavy snow.cancel为什么加ed,前面is不是已经变was了吗?