He said he has ordered a report in thirty days on what,if any, additional safety measures and technologies should be required to prevent future spills.

VOA: special.2010.05.01

that, except for the principles, maybe their families maybe not, all our money can disappear in thirty days, so we have to be cognizant of that.

这意味着除了那些最重要的人，或者是他们的家人，或者不是，我们所有的钱可以在30天之内消失，所以我们必须认识到这一点。

耶鲁公开课 - 金融市场课程节选

There's twenty-one days, there's thirty days, there's twenty-four hours. Now look at this!

有二十一天法,三十天法,二十四小时法,还有这个

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

said people need to exercise thirty minutes each day for at least five days to get the health benefits of exercise.

VOA: special.2010.06.08

People walked thirty-two kilometers a day for three days to increase public awareness and raise money to fight breast cancer.

VOA: special.2009.11.02

George Gershwin died in nineteen thirty-seven, just days after doctors learned he had brain cancer.

VOA: special.2009.02.15

That fast lasted for thirty-six days and almost killed him.

VOA: special.2009.09.06