If you're traveling in a vehicle, never attempt a water crossing.

如果你正在交通工具上，千万不要尝试过河。

Or is it his almost imperceptible limp from last year's water crossing?

还是他去年过河时几乎察觉不到的跛行？

He'd done a water crossing, but now he wanted to move onto the air.

他已经完成了水上穿越，但现在他想挑战空中穿越。