The issue of sovereignty is a red line that cannot be crossed.

主权问题是一条不能跨越的红线。

Three horses crossed the finish line together.

3匹马同时冲过终点线。

The two horses crossed the finishing line together.

两匹马同时越过终点线。

Then they crossed the state line into Mississippi.

然后他们跨越州界线来到了密西西比州。

I normally never write into magazines but Mr. Stubbs has finally crossed the line.

我通常是从不给杂志写信的，但斯塔布斯先生最后太出格了。