What dou think ___about at the meeting tomorrow?

问题描述:

What dou think ___about at the meeting tomorrow?

talking
动词ING做状语

What do you think will be talked about at the meeting tomorrow?
你认为明天的会上将讨论什么?

will be talked
在这里 do you think 是作为插入语,所以就是what will be talked about at the meeting tomorrow.
内容是被谈论的,所以用被动语态,时间为明天,所以为will be talked.