That’s right!
Absolutely!
Exactly!
Me too!
Yes, I agree!
I totally agree!
I couldn’t agree more!
I see exactly what you mean!
You're right. That's a good point.
I don’t agree!
I totally disagree!
Absolutely not!
That’s not right!
I’m not sure about that.
I agree up to a point, but ...
I see your point, but ...
That’s partly true, but ...
I'm not so sure about that.