— Excuse me, can you spare me a few minutes?

—Sorry, I haven’t ______ time to talk to you just now. I have to leave early to catch ______ 4:30 train.

A．/; /

B．the; the

C．a; the

D．the; /

BGP邻居会话建立之前，以下哪些是必须执行的（）。

A.BGP邻居必须发送Open消息

B.两BGP路由器之间必须建立TCP连接

C.手动配置并指定邻居

D.邻居间相互交换路由数据库