我们必须好好准备，一定不要有差错。

We must be well prepared, there must be no slips.

《柯林斯英汉双解大词典》

一个国家必须冒一定风险来成就伟大的事业。

A nation must take certain risks to achieve greatness.

《柯林斯英汉双解大词典》

必须办理一定的手续方能移居他国。

Certain formalities have to be gone through before you can emigrate.

《牛津词典》

All right? The first one is, that test has to involve-- shouldn't have to, the value of some variable.

好不好？第一件事是，循环开始的测试必须必须-不是一定，一些变量的值。

麻省理工公开课 - 计算机科学及编程导论课程节选

You must love loyal advisors and servants, whether they be foreigners or our own people, and spare no effort to serve the common good."

你一定要热爱俄国那些忠诚的大臣和臣民,不管他是来自外国还是国内,同时你也必须不遗余力地为公共利益服务"

耶鲁公开课 - 欧洲文明课程节选

So, empathy, caring, sympathy don't kick in, but instead there's the aggression unleashed at somebody and there has to be some level of surprise.

所以移情，关怀，同情没有发挥作用，反而是释放了别人的侵略情绪,还必须在一定程度上出人意料。

耶鲁公开课 - 心理学导论课程节选