"one has to draw the line somewhere" in Chinese (Simplified)
Definition
这个表达意思是：无论多难，总要有个做事的底线，不能什么都接受。通常用来说明必须设定界限。
Usage Notes (Chinese (Simplified))
属于半正式或口语表达。常用来说明在某事上必须划定界限，不可无限包容，多见于讨论规则或行为的时候。语气坚定但不中伤对方。
Examples
There are lots of things I can accept, but one has to draw the line somewhere.
有很多事情我可以接受，但**总得有个底线**。
He wants to eat only candy for dinner, but one has to draw the line somewhere.
他晚饭只想吃糖果，但**总得有个底线**。
If we let everyone in for free, one has to draw the line somewhere.
如果我们让所有人免费进来，**总得有个底线**。
I'd love to help, but one has to draw the line somewhere when it comes to giving out loans.
我很乐意帮忙，但在借钱这件事上，**总得有个底线**。
I don't mind staying late sometimes, but one has to draw the line somewhere if it becomes every night.
我偶尔加班没问题，但天天这样，**总得有个底线**。
She lets her kids watch TV, but one has to draw the line somewhere—no TV during meals.
她允许孩子看电视，但**总得有个底线**——吃饭时不能看。