I must down to the seas again, to the lonely sea and the sky.

余须复适彼沧海，复共空寥之海天。

youdao

These throat-singers must pass down their skills to younger generations for this tradition to survive.

VOA: special.2010.12.01

If a person has the basic concept down, regardless of numerical errors, if the person has the basic concept down, he or she must get at least five out of ten.

如果一个人有一些基本的概念，不管一些数字上的错误，如果他有基本的概念，至少都能够得到一半的分。

麻省理工公开课 - 固态化学导论课程节选

And,as Chateaubriand said,the writer, "I don't know what we must believe but we must believe in something," and he gets down on his knees and prays.

如作家夏多布里昂所言,"我不知道我们能相信什么,但我们必须相信点什么",然后他屈膝跪下开始祈祷

耶鲁公开课 - 1871年后的法国课程节选

To get there, costs must come down and technologies must improve, which would make it easier to attract capital.

FORBES: Offshore Wind Projects Could Provide Refreshing Energy Source

"The communities must sit down together and they must develop a dialogue, " he said.

BBC: News Online

We must close down the ungoverned space in which they thrive and we must deal with the grievances they use to garner support.

BBC: David Cameron