Sibling rivalry is often taken as an unexamined fact of family life -- as much a part of parenting as potty training or bedtime stories.
원문출처 : https://www.cnn.com/2020/09/16/health/siblings-get-along-better-wellness/index.html
원문출처 : https://www.cnn.com/2020/09/16/health/siblings-get-along-better-wellness/index.html