The older kind of submarine used in World War Two could stay under water for only about forty-eight hours.

VOA: special.2010.06.11

And there are very few people that you can sit down and speak to for, like, eight hours at a time.

很少有人你可以坐在一起,一次就能聊天聊8个小时。

普林斯顿公开课 - 人性课程节选

Studies have shown that over time, most humans need eight to eight and a half hours of sleep for the best health.

VOA: special.2009.08.26

And this was true only if you sat there for more than eight hours.

VOA: special.2009.07.14

"Now we have what we would call rush hour conditions or peak travel conditions for as much as eight hours during the day - about three to four hours in the morning and similar time in the evening."

VOA: standard.2010.07.26