它须能解释该发言人为什么选择这个主题，他具备什么样的资格在此发言，为什么适合受众，为什么适合在此时讨论。

A body. It explains why the subject was chosen, why the speaker is qualified to address it, why it is appropriate for this audience and why this time is appropriate to discuss it.

youdao

我选择了“我想知道为什么事情是这样的”这个主题。

I chose the topic I wonder why things are the way they are.

youdao

我选择了“我想知道为什么事情是这样的”这个主题。

I chose the topic I wonder why things are the way they are.

youdao