Now,airlines will have to check the no-fly list within two hours of being told of additions, instead of twenty-four hours.

VOA: special.2010.05.08

And for the space of four hours every night, I feel no boredom.

每晚四小时的学习，我一点也不觉得无聊。

耶鲁公开课 - 政治哲学导论课程节选

A food frequency--by the way, you also have the issue of whether the particular twenty-four hours that a person is interviewed is representative of their diet overall, because you can imagine how much your food intake varies from day to day.

食物摄取频率,顺便说下,还有一个问题,就是在选取的24小时里,测试者,是不是对总体有代表性,因为你可以想象,每天事物的摄入量都是不同的

耶鲁公开课 - 关于食物的心理学、生物学和政治学课程节选

The World Health Organization says passengers who sit still for four or more hours face a greater risk of developing blood clots.

VOA: special.2009.07.14

Americans spend the most time out of any other people in the world volunteering in average four hours a week, volunteering outside their job which may also have a social objective more than any other people in the world.

比其他任何人所花的时间都多,平均每周有四个小时做志愿者的工作，做与自身工作无关的善事,他们比世界上其他人更具社会目标。

哈佛公开课 - 幸福课课程节选

Anders Wilhelmson says the sanitation process can take as little as a couple of hours or as long as two to four weeks.

VOA: special.2010.03.15

"There is no way we can monitor the activities of each juror twenty-four hours a day.

VOA: special.2009.08.31

The Earth takes twenty-four hours to complete one full turn or revolution of three-hundred-sixty degrees.

VOA: special.2010.07.14

More than four-thousand shells had been fired during the thirty-three hours of fighting.

VOA: special.2009.08.13

During the summer, the most dangerous period for U-V rays in the United States mainland is between the hours of ten in the morning and four in the afternoon.

VOA: special.2010.07.06

He wrote this about his experience: I know that during that long and racking march of thirty-six hours over the unnamed mountains and glaciers of South Georgia it seemed to me often that we were four,not three. The American poet T.S.Eliot was influenced by Shackletons description.

VOA: special.2010.02.24