請翻譯為英文

I know that there is the existence of a boundary.

我知道, 那裡是存在著一條界線的.
1) I knew that there is a guide-line existed. (一件事或做法的界線, 或規則)
2) I knew that there is a border line existed (地方界線 such as between two countries.)
3) border line = 另一解釋是極限, 不可超越這界線.

I do know that there is a border line existed.

I understand/I know, there is a border existed

我知道, 那裡是存在著一條界線的
A boundary always exists there, I know...