Agreeing and disagreeing - phrases

Agreement

 

There are many reasons for ...

There is no doubt about it that ...

I simply must agree with that.

I am of the same opinion.

I am of the same opinion as the author.

I completely/absolutely agree with the author.

Disagreement

 

There is more to it than that.

The problem is that ...

I (very much) doubt whether ...

This is in complete contradiction to ...

What is even worse, ...

I am of a different opinion because ...

I cannot share this / that / the view.

I cannot agree with this idea.

What I object to is ...

Unlike the author I think ...