"What is today's meeting mainly about?"
Doesn't the translation need a 的 at the end? And would it be possible to say 今天的会议主要关于什么?
The previous exercise was "What was the movie about?" 这个电影是关于什么的? " Required it.
Not really, since that'd make it less formal and a meeting sounds rather formal. It'd be the opposite for a movie which sounds casual.