History records say that in only four years the area around Dawson produced more than fifty-one million dollars in gold.

VOA: special.2009.02.11

I would say absolutely. And I would say even I could notice over the past four years I feel and there is a different tenor.

我答案是肯定的，我想说,甚至我都能感受到过去四年里,学校氛围发生的变化。

普林斯顿公开课 - 人性课程节选

I have to say that Shelly Kagan is probably the best lecturer I had in my four years at Yale."

我不得不说薛立·卡刚很可能是,我在耶鲁四年所遇到的最好的演讲者“

耶鲁公开课 - 死亡课程节选

Experts at the Centers for Disease Control and Prevention say hospital treatment for likely H1N1 is most common among children up to four years old.

VOA: special.2009.11.24

Others say he was four years old.

VOA: special.2009.11.28

Cardiologists, such as Dr.Gerard Martin, say that within the last four years, doctors have learned how to perform more complex heart surgeries using catheters."

VOA: standard.2010.01.01