1. agree with

①表示同意某人或某人的意见、想法、分析、解释等 (即持同一观点)：

I don’t agree with you. 我不同意你的意见。

They agreed with this idea. 他们同意这个想法。

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 weather doesnot agree with me. 这种天气对我不适宜。

Hard work does notagree with him. 艰苦的工作对他不适宜。

③表示“与…一致”：

A verb must agree with its subjectin person and number. 动词必须和它的主语在人称和数方面保持一致。

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：

We agreed to their arrangement. 我们同意了他们的安排。

She agreed to marriage. 她同意结婚。

有时 agree to 也可用来表示“答应”一件自己不愿做的事：

I was forced to agree to it, but at heart I didn’t quite agreewith it. 我被迫答应，但内心并不完全同意。

②后接 suggestion, plan, proposal 等名词时，与 accept 同义：

Do you think he will agree to (=accept) my suggestion? 你认为他会同意 (接受)我的建议吗?

③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. 他同意同我们去。

I never agreed to Mary marrying him. 我从来没同意玛丽嫁给他。

3. agree on [upon]

①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 agreedon these terms. 双方都同意这些条件。

②后接动名词 (=agree to do sth)：

He agreed on lending (=to lend) us some money. 他同意借给我们一些钱。

Mary agreed oncoming [to come] on Monday. 玛丽同意星期一来。

4. 两点用法说明：

(1) 后接表示人的名词或代词时，一般只用 agree with。

(2) 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.