You can use "agree about". The other answer is good in all respects apart from stating that "agree about" is not possible. Dina and I clearly do not agree about this. To give some examples: "You and I agree about the meaning of this sentence then, I suppose". "We agree about the need to increase sales. Clearly we are in disagreement about the need to hire new staff." Usually, when one uses "agree about", one must also go on to talk about one is being agreed. --- You can also use "agree on". When you wish to state that you agree with a particular fact or opinion. "We agree on this then." [where 'this' is a particular fact or opinion]. "It seems that we agree on the idea of increasing the company's sales". ---- "Agree to" is fine. As the other poster has mentioned. "We have agreed to go to Paris next week". The verb does not necessarily need to be in the infinitive. Eg. "We agree to meeting every night next week then?" "We will agree to the proposals next week". "We agreed to making a cake together next Wednesday". ----- "Agree with" is fine. It means that you are agreeing with another person(s) or a particular philosophy/line of thought. "I agree with you on that". "I agree with French idea of the welfare state". -------- "Agreed at" / "To agree at" can also be used. Eg. "The proposals were agreed at their London offices back in May". "The world's environmental future will be agreed at the U.N's head offices". ----- "Agree, for" can also be used. Eg. "I agree, for the time being, that we should only be friends". This is a little informal. To be correct and formal, you should always say: "I agree that, for the time being, we should only be friends". --- "Agree in" can also be used. For instance, "It appears that we agree in principle then". "The treaty was agreed in Paris during the early 19th century". ---- If you want to know about "agree" with any other preposition or in any other context just let me know.

agree on, agree about a thing, or an idea agree with a person on something or about something

I have never heard " to agree about" . Only ' agree on, in , to and with' They all refer to the idea of acceptance. Agree on a plan suggests two or more people have the same idea about what should be done. Agree with a proposal or another person when you accept that proposal or the person's point view because both are the same - yours and theirs. Agree to often plus an infinitive as in: agree to do something as when you have volunteered to do something. I hope it helps