By looking up the elements in the rings for a givenyear, scientists can tell what elements were in the air that year.
通过查找某一年年轮中的元素，科学家可以知道那一年空气中的元素是什么。
2
The startling finding was that the average Medicare patient saw a total of seven doctors—two primary care physicians and five specialists—in a givenyear.
令人吃惊的发现是，医保患者一年内要看7名医生——2名初级保健医生和5名专科医生。
3
Kona and Hilo have approximately the same rainfall in a givenyear.