Milton makes a covenant with the reader. It's as if he's signing a contract because he's asking for credit here.

他与读者签了契约，就好像,因为他要借款所以签了份合同一样。

耶鲁公开课 - 弥尔顿课程节选

The government, after this time, did issue contracts to manufacturing companies to produce new quantities of the virus.

在此事件之后,美国政府,和病毒生产企业签了,生产一些病毒的合同

耶鲁公开课 - 生物医学工程探索课程节选

We know they can't sign a legal agreement, but let's take that off the table.

我们都知道不能签署违法合同,那就只能私底下签协议了

耶鲁公开课 - 博弈论课程节选

But if you need a slave representing your business, and you live in Rome and you need somebody in Ostia, the port city of Rome, to be able to be there and watch your imports and your exports of your business, you need someone who can sign contracts, who can lend money, who can borrow money, who can do things like that.

如果你需要一名奴隶代理你的生意，如果你住在罗马，需要有人，在罗马奥斯蒂亚港口,照看你的进出口生意，就得要能签合同，可以放债贷款，及其他类似事务的人。

耶鲁公开课 - 新约课程节选

Why wouldn't writing a contract here work?

为什么他们不能签这样的合同

耶鲁公开课 - 博弈论课程节选

Well, one thing that goes wrong is that suppose Coke and Pepsi were able to either to write a contract or whatever to sustain joint monopoly output at this high price, this price which is actually producing positive profits in the industry it is going to turn out, therefore the price is going to be above costs.

我来说吧,问题出在这里了,假设可口可乐和百事达成了协议,不管签的是协议还是合同,只要能通过协约维持垄断产出,通过制定高价来达到正的利润就行,这样价格是高于成本的

耶鲁公开课 - 博弈论课程节选