①同意
I agree with/to/on
That’s a good point 
→I agree to this decision, but not to refuse any refund.

②大賛成
I couldn’t agree more 
You can say that again 
→I couldn’t agree more you shouldn’t invest 
to stock markets now.

③ほぼ同意
I suppose 
I think I agree with you 
→I suppose the decision that your school has decided to postpone.