I'm an only child? It's good to have a big sister. Tell me about it.

This bosom friend, it is good to find a husband with a sister. First, the elder sister can take care of her husband. Second, something can be discussed with elder sister. Third, we have a relative, and when we have children, we can have cousins. Fourth, the elder sister can have a lot of intimacy with her sister-in-law, and have one more relative.