商定的英文：
agree on
agree upon
agreement
Arrange
come to an arrangement

参考例句：

We must arrange about that.
我们应商定那件事。

The two sides have agreed on the date of negotiation.
双方商定了谈判的日期。

We agreed on a price for the car.
我们商定了汽车的价格。

Appointments can be made by arrangement.
约见时间可以商定解决。

The two countries negotiated a peace treaty.
两个国家商定了和平条约。

We agree to pay the rent quarterly or on a quarterly basis.
我们商定按季度付租金。

Detailed provisions concerning such co-operation will be worked out later through consultation.
有关合作细则，由双方另行商定。

Once the price had been agreed,a deal was quickly concluded.
价格一经商定,交易很快就达成了.

They have just arrived to negotiate a formal agreement with us on the boundary question.
他们刚来和我们就边界问题商定正式协议。

Once the content is agreed upon, new draft guidelines will be circulated for comment.
内容一旦商定，新的准则草案就将传阅以听取意见。

agree是什么意思：
v. 商定，约定；同意；赞成；承认；一致；符合；适宜

The day after, she agreed.
一天之后，她同意了。

Birds in their little nests agree
同巢之鸟相处好;家和万事兴

Friends agree best at distance
君子之交淡如水

upon是什么意思：
prep. 在...上；紧接着；逼近；根据；走上...；爬上...

He stepped upon the alter.
他走上圣坛。

To bear hard upon;press.
使痛苦不堪对某人施加困难；逼迫

press hard upon
进逼|压迫|穷追

agreement是什么意思：
n. 同意；协议；一致

rescind an agreement
废除协定

This will be retroactive agreement.
这些是追溯以往的合约。

They have a tripartite agreement.
他们有一个三者间的协议。