It's illegal, so they can't sign that as a contract, but they they can just agree to do it.

因为是违法的,合同也就无效了,不过他们可以私下达成默契

耶鲁公开课 - 博弈论课程节选

He is the secret head of a large illegal gambling ring which use the computer for its operations.

他是一个秘密的，大的，非法的赌博团伙的头,那个团伙用这个电脑来操作。

哈佛公开课 - 计算机科学课程节选

It was illegal--it's still illegal in France to name a baby a name that is not officially approved, absolutely--or even to adopt one.

给婴儿取一个没有被官方认可的名字,是违法的,至今仍是如此,完全不被允许,领养也不行

耶鲁公开课 - 1871年后的法国课程节选

It's illegal to sign an agreement, to sign a contract saying you're going to restrict quantities.

签订这样限制产量的协议,属于违法行为

耶鲁公开课 - 博弈论课程节选

So, Achilles is not doing anything sort of illegal or unconstitutional, but he's doing something that's really out of line from a normal point of view.

阿喀琉斯并没做什么不合法律的行为,但从我们的角度来看,他的行为的确过分了

耶鲁公开课 - 古希腊历史简介课程节选

But actually, hazing is illegal but a remarkably successful tool.

实际上，捉弄他人是违法的,但它却是非常有效的一种手段。

耶鲁公开课 - 心理学导论课程节选

If I join a fraternity-- it is also by the way illegal but if I were to join a fraternity and they say, "Welcome to the fraternity, Dr. Bloom.

如果我要加入一个兄弟会…,提醒大家，这是非法的,如果我要加入一个兄弟会，so，–,他们说”欢迎加入我们兄弟会，Bloom博士“

耶鲁公开课 - 心理学导论课程节选