George. W. Bush, _______ President of the United States, is to visit China  _______ third time.

A．a；a

B．the；a

C．/；a

D．/；the

带宽型障碍申请挂起条件有（）

A.电信可控段正常而用户无法配合

B.客户要求的测试、监控等操作

C.业务恢复而用户要求观察

D.障碍修复而用户无法确认