Having been attacked by terrorists, ______.

A．doctors came to their rescue

B．the tall building fell down

C．an emergency measure was taken

D．warnings were given to tourists

阅读下面的《三国演义》选段，回答问题。

周瑜大张筵席，奏军中得胜之乐，轮换行酒。告众官曰：“此吾同窗契友也，虽从江北到此，却不是曹家说客，公等勿疑。”

周瑜所言“同窗契友”是指谁？围绕此人的到来，周瑜做了哪些安排？请简述相关情节。