Their memory improved significantly, so their intelligence level as taking by tests before and after compared to control group improved significantly after a single week.

他们的记忆力有明显改善，他们的智力水平,在实验前后进行测试，再与对照组相比,在仅仅一周后就有明显改进。

哈佛公开课 - 幸福课课程节选

Juvenile offenses: control group versus intervention group-- no difference.

少年犯罪：,对照组与干预组没有区别。

哈佛公开课 - 幸福课课程节选