"by themselves" in Chinese (Simplified)
他们自己单独
Definition
用于表示人们独自做某事，没有别人的帮助；也可以指某人单独一人，没有陪伴。
Usage Notes (Chinese (Simplified))
'By themselves' 只能用于复数主语，表示独立做事或独处。单数主语用 'by himself/herself'。语气中性，适合各种场合。常用于动作后面。
Examples
The children can eat by themselves now.
孩子们现在可以**自己**吃饭了。
They fixed the car by themselves.
他们**自己**修好了车。
The birds built the nest by themselves.
鸟儿们**自己**筑了巢。
They like being by themselves on weekends.
他们喜欢周末**独处**。
Don’t worry, the kids are fine by themselves for a few hours.
别担心，孩子们**自己**待几个小时没问题。
Sometimes, they just want to travel by themselves and explore new places.
有时候，他们只想**自己**去旅行探索新地方。