The two other groups, the massage therapy and acupuncture treatments not known to ease depression, were used as controls.

VOA: standard.2010.03.03

The third group that was given the candies and put in a positive playful mood outperformed the other two groups significantly-- they thought about more options and they actually came up with better solutions with that problem.

第三组得到糖果,并获得积极愉快的心情,明显比另外两组有更好表现-,他们考虑更多选择,得出更好的问题解决办法。

哈佛公开课 - 幸福课课程节选

If vaccine supplies are limited, then the committee says two groups of children should be vaccinated before other children.

VOA: special.2009.08.05

"The two groups who have the most in common are killing each other,"

VOA: standard.2009.11.25