We're crossing the international date line.

我们正越过国际日界线。

We're crossing the International Date Line.

我们正越过圈际日界线。

We have crossed the International Date Line.

我们已经飞过了国际日期变更线。

The International Date Line is a geographical noun.

国际日期变更线是个地理名词。

Planes have to fly over the International Date Line.

飞机得飞越国际日际日期变更线。