He didn't enlarge on the form that the interim government and assembly would take.

他未详述临时政府和议会将会采取的形式。

I am really interested with the topic of your speech. Can you enlarge on what you mentioned this afternoon?

我对您演讲的主题很感兴趣。您能详细谈谈您今天下午提到的内容吗?

Let me enlarge on the topic.

让我进一步说明一下这个题目。

I would like to enlarge on this theme.

我想就这一主题进行详述。

Can you enlarge on what has already been said?

你能把所说的事再详尽地说说吗？