If you ask someone what they are driving at, you ask that person what they really mean.

I don't see what you're driving at. 我不明白你的意思。

What exactly are you driving at, Sir?

That is exactly what I think he was driving at last night during the interview.

I suppose what I'm driving at is that simply because you went to university doesn't make you intelligent.

The audience got what the playwright was driving at straight away.