Half of the overall test group of more than 16,000 people received the doses, while the other 8,000 people in the trial received a placebo.

VOA: standard.2009.10.20

And then he had them take a comparative and control group an intelligence test and a memory test.

然后他对比他们和对照组的,智力和记忆力测试结果。

哈佛公开课 - 幸福课课程节选

So, you didn't know at the beginning, you knew you were enrolled in the trial, they gave you a shot, you didn't know whether you were part of the real group that got the test vaccine or the placebo group that got the control; turned out that Bonnie was part of the control group.

一开始你可能不清楚全过程,你只知道你参与了一项试验,他们给你打了一针,你不知道你是属于接种了,试验疫苗的真实试验组,还是属于被注射了安慰剂的空白对照组,结果显示,邦妮属于对照组

耶鲁公开课 - 生物医学工程探索课程节选

So the group started a competition called the National Geographic Bee to test students' knowledge about places around the world.

VOA: special.2009.05.29

A group of volunteers who had not lost their arms performed the same test.

VOA: special.2009.03.10

And I think that will stand the test of time." State Department officials traveling with Secretary Clinton say she also discussed the Group of Eight leading industrialized nation's That money is in addition to emergency humanitarian programs, and is meant to fight hunger by enabling small farmers to produce more of their own food by improving productivity.

VOA: standard.2009.08.16