The study used a "cross-over" design, which allowed each subject to serve as his or her own comparison group.
这个研究试验采用了交叉设计，这样每一个研究对象的对照组就是他（她）自己。
2
Method Cross-sectional investigation was applied to study 1941 elderly aged 60 or over years of age with questionnaire of elderly comprehensive health function.
方法对上海市天平街道1941名60岁以上社区老年人的健康状况进行描述性分析。
3
Walgren goes over what White said about the Beagle study under direct and cross.