油漆工正在船体上重新标记吃水线。

The painter is re-marking the ___waterline on the hull of the ship.

涨潮后，沙滩上留下了一条清晰的水位线。

After high tide, a clear ___waterline was left on the sandy beach.

船身的油漆必须在水线以下特别防水。

The paint on the hull must be especially waterproof below the ___waterline.