The studies found that the mistake rate in two intensive-care areas decreased when interns worked fewer hours.

VOA: special.2010.07.13

The Minnesota Twin study, one of the most famous studies in the field of psychology, was done by Lykken and Tellegen,two prominent psychologists.

明尼苏达州的双胞胎研究，一个在心理学领域非常有名的研究，是两个杰出的心理学家Lykken和Tellegen做的。

哈佛公开课 - 幸福课课程节选

Two studies exploring the subject were published last month in the Archives of Pediatric and Adolescent Medicine.

VOA: special.2009.02.03

Two studies released last week found that taking medication daily reduced the risk of infection in heterosexuals.

VOA: special.2011.07.20

Two new studies have investigated why fewer females,compared to males, study and work in the so called STEM subjects in the United States.

VOA: special.2010.04.01

Two studies of the social networking site recently appeared in the Archives of Pediatric and Adolescent Medicine.

VOA: special.2009.02.18

Two studies showed ways in which anti-H.I.V.drugs could permit infected women to breastfeed their newborns with less risk of passing the virus to them.

VOA: special.2009.07.29

In other studies, bone marrow transplants cured severe sickle cell disease in almost two hundred children.

VOA: special.2009.12.16

She finished her studies in psychology in nineteen forty-two.

VOA: special.2009.10.18