1. agree with用于以下用法:

①表示同意某人或某人的想法(即持同一观点),后面常接sb和what引导的句子:

I don’t agree with you. 我不同意你的意见。

I agree with what you say. 我同意你说的。

②表示“ (食物、天气、工作等)对…适宜”:

The dampness of the forest did not agree with him physically. 他的身体不能适应森林的潮湿。

I don't think the food here agrees with me.

我觉得这里的食物不对我的胃口。

③表示“与…一致”:

What he does does not agree with what he says. 他言行不一致。

2. agree to

①主要用来表示一方提出一项建议、安排、计划等,另一方同意协作:

They had little choice but to agree to his suggestion.

他们别无选择,只好接受他的提议。

Is he going to agree to our plan? 他会同意我们的计划吗?

②其后既可接动词原形 (此时to是不定式符号),也可接动名词 (一般有逻辑主语,此时 to是介词):

He agreed to go with us. 他同意和我们一起去。

I never agreed to lucy marrying him. 我从来没同意露西嫁给他。

3. agree on [upon]

主要指双方通过协商而取得一致意见或达成协议:

We agreed on the price. 我们就价格达成了一致意见。

Both sides agreed on these terms. 双方都同意这些条件。

注意:agree 不能接不定式的复合结构,所以汉语的“同意某人做某事”,不能直译为 agree sb to do sth, 而应根据情况改用其它结构:

  他们同意我去。

  正:They agreed to let me go.

  正:They agreed to my going.

  误:They agreed me to go.