AVL规则 10.1.2 补给线的规定：A supply line is a series of adjacent hexes
going from the unit to a friendly supply source. There is no limit to
the number of hexes a supply line can pass through. However, it
cannot pass through an enemy-occupied hex, or an enemy ZOC
unless the hex contains any friendly combat units or HQs. A supply
line cannot cross unbridged major river hexsides, impassable
hexsides, or pass through Water hexes.
