If the only sister of your mother's only brother has an only child, what is that child to you?

如果你妈妈唯一的弟兄的唯一的姐妹有个唯一的孩子，这个孩子是你什么人？

youdao

We chose for our victim the only child of an influential citizen named Ebenezer Dorset.

VOA: special.2011.01.22

The government has made small adjustments to the policy (notably by allowing an only child who is married to another only child to have more than one child) and may adapt it further.

ECONOMIST: Demography

For an only child from the city, supervised and scrutinized, it was unheard-of freedom.

WSJ: A Horse-Crazy Girl's Separation Vacation

My one living daughter is somehow a little sister, a big sister and yet an only child.

NPR: The Human Body's Frailty and Splendor